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Lipase-catalyzed kinetic resolution of γ-cyclogeraniol by Candida antarctica lipase B yielded 23% of enantiomerically pure (S)-γ-cyclogeraniol. (+)-trixagol and (+)-luffarin-P were synthesized from the obtained (S)-γ-cyclogeraniol, and the absolute configuration of natural (+)-luffarin-P was determined to have an S configuration by our first synthesis of (S)-luffarin-P for the first time.

Context and objective: The present study is to elucidate the comparative inhibition of tetrameric carbonyl reductase (TCBR) activity by alkyl 4-pyridyl ketones, and to characterize its substrate-binding domain.Materials and methods: The inhibitory effects of alkyl 4-pyridyl ketones on the stereoselective reduction of 4-benzoylpyridine (4-BP) catalyzed by TCBR were examined in the cytosolic fraction of pig heart.Results: Of alkyl 4-pyridyl ketones, 4-hexanoylpyridine, which has a straight-chain alkyl group of five carbon atoms, inhibited most potently TCBR activity and was a competitive inhibitor. Furthermore, cyclohexyl pentyl ketone, which is substituted by cyclohexyl group instead of phenyl group of hexanophenone, had much lower ability to be reduced than hexanophenone.Discussion and conclusion: These results suggest that in addition to a hydrophobic cleft corresponding to a straight-chain alkyl group of five carbon atoms, a hydrophobic pocket with affinity for an aromatic group is located in th...

The addition of 4 eq of chloral to osmundalactone (4S,5R)-4 gave quantitative formation of the hemiacetal derivative (4S,5R)-8, which was treated with methane sulfonic acid to afford the intramolecular Micheal addition product (+)-(3S,4S,5R)-9 possessing a 3,4-cis-dihydroxy-δ-lactone in 78% overall yield from (4S,5R)-4. The obtained (+)-(3S,4S,5R)-9 was subsequently converted to methyl D-digitoxoside (pyranoside) (12) in 13% overall yield and methyl D-digitoxoside (furanoside) (12) in 20% overall yield. The reaction of benzyl-osmundalactone (4R,5S)-3 and MeOH in the presence of Amberlyst A-26 as a basic catalyst gave 3,4-trans-δ-lactone (-)-(3S,4R,5S)-20 in 28% yield and 3,4-cis-δ-lactone (-)-(3R,4R,5S)-21 in 45% yield. Dibal-H reduction of (-)-(3S,4R,5S)-20 followed by catalytic hydrogenation gave L-oleandrose (6) in 86% overall yield, while Dibal-H reduction of (-)-(3R,4R,5S)-21 followed by catalytic hydrogenation provided L-cymarose (7) in 85% overall yield.

For the purpose of preparation of optically active aminoalcohol congeners possessing both hydroxyl- and dialkylamino-substituted vicinal chiral carbons, lipase-assisted acylation of methyl (2E,4R*,5S*)-4-(N-benzyl-N-methyl)amino-5-hydroxyhex-2-enoate (4) using CAL-B with vinyl hexanoate as an acyl donor was carried out to give (4S,5R)-hexenoate (7) (44%, 99.2% ee) as the reaction product and (4R,5S)-alcohol (4) (46%, 98.2% ee) as the unreacted starting material. The E-value of the present lipase-assisted resolution was estimated to be more than 1000. Thus obtained acylated product was successfully converted into methyl β-d-vicenisaminide (12).

This review summarizes the chemoenzymatic synthesis of the biologically active natural products based on a combination of chemical diastereoselectivity and enzymatic enantioselectivity using biocatalyst. Asymmetric reduction of 2-methyl-3-keto ester with yeast gave the optically active syn-2-methyl-3-hydroxy ester, which was converted to natural product such as (-)-oudemansin B. Asymmetric hydrolysis of 3-acetoxy-2-methy esters possessing syn- or anti-structure afforded the optically active 3-hydroxy-2-methyl esters and 3-acetoxy-2-methy esters corresponding to the starting material. One of these optically active 3-hydroxy-2-methyl esters was converted to aglycone of macrolide, venturicidins A and B possessing 10 chiral centers. Both primary alcohols possessing a chiral center at β-position of hydroxyl group and secondary alcohols were subjected to the lipase-assisted acylation in the presence of acyl donor to afford the optically active esters and the optically active alcohols corresponding to the starting material. These optically active compounds were converted to the biologically active natural products such as bisabolane type sesquiterpenes, decaline type diterpenes or triterpenes, nikkomycin B, (+)-asperlin, (-)-chuangxinmycin, (-)-indolmycin, cystothiazoles melithiazols, myxothiazols and piericidins possessing antifungal and cytotoxicic activities, inhibition of NADH oxidation, etc. Reaction of primary alcohol and glucose using immobilized β-glucosidase gave alkyl β-glucosides in high yield. Pentaacetate of allyl β-glucoside was subjected to Mizoroki-Heck type reaction with phenylboronic acid derivatives to give phenylpropenoid β-D-glucopyranosid congeners.

The total synthesis of methyl β- d -vicenisaminide 1 has been achieved. In this approach, the synthesis of enantiomerically pure methyl (4 R ,5 S )- and (4 S ,5 R )-4-azido-5-hydroxy-2( E )-hexenoates 2 was established by enzymatic resolution of (±)- anti -5-acetoxy -4-azido-2( E )-hexenoate 4 . Another stereogenic center was introduced by base-catalyzed intramolecular conjugate addition of a hemiacetal-derived alkoxide nucleophile obtained by the reaction of methyl (4 S ,5 R )- N -4- tert -butoxycarbonyl- N -methylamino-5-hydroxyl-2( E )-hexenoate 8 and benzaldehyde in the presence of a base.

The reaction of 2,3-anti-2-tert-butyldimethylsiloxy-3-substituted butanal derivative [anti-B, (±)-10 and (±)-16] derived from trans-(2,3)-epoxy butanoate (1) with carbon nucleophiles [α-furyl anion, acetate anion, and indium (In)-assisted allyl anion] has been investigated to give selectively the anti-, anti-adduct D. This anti-stereoselection could be explained by the Felkin-Anh transition state model. Thus obtained anti-, anti-adducts (±)-17 and (±)-38 were formally converted to natural products, (±)-asperlin (2) and (±)-olivose (4), respectively. The major anti-, anti-adduct (±)-26 was converted to (±)-digitoxose (3), while the minor anti-, syn-adduct (±)-27 was also converted to (±)-olivose (4). The reaction of (±)-10 with tert-butyl acetate anion gave predominantly afforded the anti-, anti-adduct (±)-23, which was converted to (±)-1,5-dideoxyhexitol (25). Alternately, the reaction of 2,3-syn-2-tert-butyldimethylsiloxy-3-p-methoxyphenoxy butanal derivative [syn-B, (±)-14] derived from trans-(2,3)-epoxy butanoate (1) with carbon nucleophile (In-assisted allyl anion) afforded a ca. 1 : 1 mixture of the syn-, anti-adduct E [(±)-32 or (±)-34] and syn-, syn-adduct F [(±)-33 or (±)-35]. After separation of this mixture, (±)-34 and (±)-35 were separately converted to (±)-oliose (5) and (±)-boivinose (6), respectively.

The 7-endo Friedel–Crafts cyclization of arylpropyl vinyloxiranes was found to proceed regio- and stereoselectively to afford polyfunctional seven-membered carbocycles in excellent yields.

The convergent syntheses of (+)-piericidin A 1 1 and (−)-piericidin B 1 2 have been achieved based on classical Julia-Lythgoe olefination between 4-hydroxy-5,6-dimethoxy-3-methyl-2-[5-oxo-3-methyl-pent-(2 E )-enyl]-pyridine 3 corresponding to the left half of the final molecule, and chiral phenyl sulfones, (4 R ,5 R )-2,4,6-trimethyl-5-methoxy-1-phenylsulfonyl-octa-(2 E ,6 E )-diene 20 and (4 R ,5 R )-5- tert -butyldimethylsiloxy-2,4,6-trimethyl-1-phenylsulfonyl-octa-(2 E ,6 E )-diene 33 , corresponding to the right halves. The construction of the two stereogenic centers in the right half of piericidins was achieved based on lipase-catalyzed hydrolysis of methyl (2,3)- anti -3-acetoxy-2,4-dimethyl-hex-(4 E )-enoate (±)- 22 .

All stereoisomers of 2-allyl-3-hydroxy-2-methylcyclopentanones 2 – 5 were prepared in high conversion and in an optically pure form by microbial reduction and oxidation. The reduction of symmetric diketone 1 by Geotrichum candidum NBRC 4597 under anaerobic conditions gave 2 in 83% yield (98% conversion), >99% de, and >99% ee, whereas the reduction of 1 by G. candidum NBRC 5767 under aerobic conditions gave 3 in 75% yield (99% conversion), >99% de, and >99% ee. Oxidation of meso -diol 6 by G. candidum NBRC 5767 under aerobic conditions afforded 4 in 83% yield (99% conversion) and >99% ee, while oxidation of meso -diol 7 by Mucor heimalis IAM 6095 in the presence of cyclohexanone as a co-oxidant afforded 5 in 68% yield (75% conversion) and >99% ee.

The optical resolution of racemic albicanol ( rac - 1 ) based on the lipase-catalyzed transesterification by using vinyl myristate as an acyl donor afforded (8a R )- 1 (99% ee) in 43% yield and (8a S )- 1 (99% ee) in 37%. E value of the enzymatic reaction was 56.7 which was superior to that of the reported value ( E = 25) by using isopropenyl acetate as an acyl donor. As the synthetic application of obtained (8a R )- 1 , (−)-copalic acid ((8a R )- 3 ) and (−)-copalol ((8a R )- 4 ) were synthesized from (8a R )- 1 in 35% and 34% total yield, respectively.

The lipase-catalyzed enantioselective acetylation of racemic methyl (4S∗,5S∗)-4-aryl-5-hydroxyhex-2(E)-enoates 1a–h was performed and efficient resolutions were achieved (E >400) by using CAL-B. After brosylation of the obtained optically active 1a–h, solvolysis of brosylates 13a–h afforded the corresponding methyl (4S∗,5S∗)-5-aryl-4-hydroxyhex-2(E)-enoates 3a–h (26–94% yield). The yields of 3a and 3c on the solvolysis of the corresponding 13 were 92% and 40%, respectively, while solvolysis of the corresponding tosylate was reported at 70% and 17%, respectively. This procedure is a facile and practical route to the synthesis of bioactive and optically active bisabolane-type sesquiterpenes.

The first synthesis of (+)-myxothiazol A 1 was achieved based on a modified Julia olefination between (3,5 R )-dimethoxy-(4 R )-methyl-6-oxo-(2 E )-hexenamide 3 , corresponding to the left side of the final molecule, and 4-(2″-benzothiazolyl)sulfonylmethyl-2′-[(1′″ R ),6′″-dimethylhepta-(2′″ E ),(4′″ E )-dienyl]-2,4′-bithiazole 6, corresponding to the right side. The synthesis of (+)-myxothiazol Z 2 was also achieved based on modified Julia olefination between (3,5 R )-dimethoxy-(4 R )-methyl-6-oxo-(2 E )-hexenoate 4 , corresponding to left side of the final molecule, and ( S )-sulfone 6 .

First syntheses of sesquiterpene quinones (-)-tauranin and (-)-BE-40644 which exhibited strong cytotoxicity against several cancer cell lines, were achieved from (8aS)-albicanol obtained by enzymatic optical resolution. By comparison of the sign of specific rotation between synthetic (12bS)-BE-40644 and natural (-)-BE-40644, the absolute configurations of natural (-)-BE-40644 were determined to be 4aS, 6aS, 12aR, 12bS.

Convergent syntheses of (14R,15)- and (14S,15)-dihydroxycystothiazole A 4 were achieved based on a Julia-Kocienski coupling between the functionalized aldehyde (2E)-6 or (2Z)-6, corresponding to the left-side, and chiral sulfones (14R)-16 and (14S)-16, bearing a bithiazole moiety corresponding to the right-side, respectively. The absolute configuration of natural (14,15)-dihydroxycystothiazoles A 4 was determined to be (4R,5S,14S) by comparison of the physical data, including the sign of specific rotation, between synthetic (2E,4R,5S,6E,14S)-4 and natural 4. Deprotections of the silyl group and cyclopentane moiety of the coupled product (2E,4R,5S,6E,14R)-17 gave (14R,15)-dihydroxycystothiazole C 5, which was consistent with natural 5 corresponding to the minor isomer, including the sign of specific rotation. Likewise, deprotection of the silyl group and cyclopentane moiety of the coupled product (2E,4R,5S,6E,14S)-17 afforded (14S,15)-dihydroxycystothiazole C 5, which was consistent with natural 5 corresponding to the major isomer, including the sign of specific rotation. Finally, convergent synthesis of 14-hydroxycystothiazole C 3 was achieved based on the modified (one-pot) Julia olefination between the aldehyde (2Z)-6 and bithiazole sulfone 22. The absolute configurations of natural 14-hydroxycystothiazole C 3 were confirmed to be (4R) and (5S). Methylation of synthetic 3 gave cystothiazole B 2.

We describe an intriguing new example of a parallel kinetic resolution; an asymmetric cyclization–carbonylation of propargyl ketols catalyzed by palladium(II) with chiral bisoxazoline (box) ligands. The 2S,3S enantiomer of (±)-6 was preferentially converted to 13 (45–49% yields, 37–46% ee), and the 2R,3R enantiomer of (±)-6 was preferentially converted to 14 (21–23% yields, 92–97% ee). As an application of this reaction, formal synthesis of (+)-bakkenolide A was achieved.

Syntheses of (+)-asperlin 1 were achieved via two different synthetic routes. 1,2-Addition of α-furyl anion to (2R,3S)-2-tbutyldimethylsilyloxy-3-chlorobutanal 6 gave (1S,2R,3S)-1-(2-furyl)-2-tbutyldimethylsilyloxy-3-chlorobutanol 7, which was converted to the chiral intermediate, (1S,2R,3R)-1-(2-furyl)-2,3-epoxybutanol 8 (37% overall yield from 6) for the synthesis of (+)-1. The second synthesis of (+)-asperlin 1 from (2R,3S)-6 was achieved in 8% overall yield, based on a combination of the indium-assisted stereoselective addition of 3-bromopropenyl acetate 9 to (2R,3S)-6 and the ring closing metathesis (RCM) using Grubbs catalyst.

Treatment of 1-allenyl-1-diethynyl acetates in the presence of a Au or Pt catalyst (5 mol%) in toluene at room temperature, followed by methanolysis, gave 4-methylene-2-cyclopentenones. The new cationic bisoxazoline (box)-Au(III) complex {( S, S)-Phbox- or [( R, R)-Bnbox AuCl 2 ]SbF 6 } accelerated the reaction, providing the products in moderate yield (60-69%).

Oxidative cyclization–carbonylation of 2-alkyl-2-propargylcyclohexane-1,3-diones mediated by Pd(TFA)2/2,2′-isopropylidenebis[(4R)-4-(3,4-dimethoxyphenyl)-2-oxazoline] 28 afforded bicyclic-β-alkoxyacrylates in 51–74% yields with 72–82% ee. The products containing quaternary carbon were converted to optically active hydrindanes 33.

In recent years, the technology which heightens the output per unit volume by equipping a stator with a high-density coil using divided cores is used widely in order to improve the motor output or the motor efficiency. Since the divided cores really tend to generate work errors compared with the non-divided core, magnetic energy changes by few work errors, and there is a problem that the cogging torque known as torque ripple becomes large. Therefore, in the motor which has divided cores, it is useful industrially to obtain the manufacturing method which reduces cogging torque effectively by simple process.In this research, by using the concentrated magnetomotive force model, the technique of writing the cogging torque resulting from the error of the inside diameter form of a stator as a vector was introduced, and the validity was verified. The rotary lamination method was proposed as a method of reducing cogging torque by making each other offsetting combining two or more torque vectors, and the effect was verified by experiment. In the experiment, the rotary lamination is realized by the manufacturing method with the divided cores which are pierced in the circular shape by a metallic mold. There will be room to study offsetting the torque vector of other factors by control the torque vector arbitrarily using the rotary lamination method of the divided cores.

Total syntheses of (+)-coronarin A (1), (+)-coronarin E (2), (+)-austrochaparol (3) and (+)-pacovatinin A (4) were achieved from the synthetic (+)-albicanyl acetate (6). Dess-Martin oxidation of (+)-albicanol (5) derived from the chemoenzymatic product (6) gave an aldehyde (7), which was subjected to Julia one-pot olefination using beta-furylmethyl-heteroaromatic sulfones (8 or 9 ) gave (+)-trans coronarin E (2) and (+)-cis coronarin E (12) with high cis-selectivity. The synthesis of (+)-coronarin A (1) from (+)-trans coronarin E (2) was achiev-ed, while (+)-cis coronarin E (12) was converted to the natural products (+)-(5S,9S,10S)-15,16-epoxy-8(17),13(16),14-labdatriene (13) and (+)-austrochaparol (3). By the asymmetric synthesis of (+)-3, the absolute structure of (+)-3 was determined to be 5S, 7R, 9R, 10S configurations. Homologation of (+)-albicanol (5) followed by allylic oxidation gave (7 alpha)-hydroxy nitrile (17), which was finally converted to the natural (+)-pacovatinin A (4) in 8 steps from (+)-albicanol (5).

The reported enzymatic resolution products {acetate of (1S,4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal} (8aS)-5 (>99% ee)] and [(1R,4aR,8aR)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal (8aR)-4 (98% ee) were converted to (+)-alpha-polypodatetraene (1) and methyl (5R,10R,13R)-labda-8-en-15-oate (2), respectively. For the synthesis of (5R,10R,13R)-2, chiral isoprene congener (3S)-26 corresponding to the right part of 2 was synthesized based on the lipase-assisted resolution of (+/-)-2-methyl-3- (p-methoxyphenyl)propanol (17).

The enzymatic resolution products [(1 R ,4a R ,8a R )-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo- trans -naphthalene-1-methanol-2-ethylene acetal (8a R )- 7 (98% ee) and {acetate of (1 S ,4a S ,8a S )-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo- trans -naphthalene-1-methanol-2-ethylene acetal} (8a S )- 9 (>99% ee)] obtained by the lipase-catalyzed enantioselective acetylation of (±)- 7 in the presence of vinyl acetate as an acyl donor were converted to the α,β-unsaturated ketones (8a R )- 6 and (8a S )- 6 , respectively. Concise syntheses of (+)-totarol 1 , (+)-podototarin 2 and (+)-sempervirol 3 were achieved based on Michael reactions between (8a S )- 6 and the appropriate β-keto ester followed by aldol condensation. The first chiral syntheses of (+)-jolkinolides E 4 and D 5 were achieved from (5 R ,10 R ,12 R )-12-hydroxypodocarpa-8(14)-en-13-one 15 derived from (8a R )- 6 .

The TMSOTf-promoted Friedel–Crafts-type reaction of vinyloxirane 3 having a nitrogen atom at the benzylic position was found to proceed with a highly selective 7- endo mode to afford hydro-2-benzazepine 4 in high yield.

(±)-(4,5-anti)-4-Benzyloxy-5-hydroxy-(2E)-hexenoic acid 6 was subjected to δ-lactonization in the presence of 2,4,6-trichlorobenzoyl chloride and pyridine to give the α,β-unsaturated-δ-lactone congener (±)-7 (87% yield) accompanied by trans–cis isomerization. This δ-lactonization procedure was applied to the chiral synthesis of (+)-(4S,5R)-7 or (−)-(4R,5S)-7 from the chiral starting material (+)-(4S,5R)-6 or (−)-(4R,5S)-6. Deprotection of the benzyl group in (+)-(4S,5R)-7 or (−)-(4R,5S)-7 by the AlCl3/m-xylene system gave the natural osmundalactone (+)-(4S,5R)-5 or (−)-(4R,5S)-5 in good yield, respectively. Condensation of (−)-(4R,5S)-5 and tetraacetyl-β- d -glucosyltrichloroimidate 22 in the presence of BF3·Et2O afforded the condensation product (−)-8 (97% yield), which was identical to tetra-O-acetylosmundalin (−)-8 derived from natural osmundalin 9.

Amberlite XAD-7, a hydrophobic polymer, was used to change microbial reaction of ketones from reduction to Baeyer-Villiger (BV) oxidation. Thus, D. magnusii NBRC 4600 and G. reessii NBRC 1112 could catalyze the BV reaction of ketones in the presence of the polymer while reduction of the substrates proceeded, and BV oxidation was scarcely found in the absence of the polymer.

Both enantiomers (8a R )- 7 and (8a S )- 7 of bicyclofarnesol were synthesized from the enzymatic resolution products (1 R ,4a R ,8a R )-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo- trans -naphthalene-1-methanol-2-ethylene acetal (8a R )- 5 (98% ee) and acetate of (1 S ,4a S ,8a S )-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo- trans -naphthalene-1-methanol-2-ethylene acetal (8a S )- 6 (>99% ee), respectively. The formal synthesis of (+)-wiedendiol 1 was achieved via a coupling reaction of an ate complex derived from 1,2,4-trimethoxybenzene with allyl bromide (8a S )- 8 derived from (8a S )- 7 . The total synthesis of (+)-norsesterterpene diene ester 2 was achieved, based on the synthesis of (13 E ,10 S )-α,β-unsaturated aldehyde 12 , derived from (8a S )- 7 , followed by the selective construction of the (3 E ,5 E )-diene moiety including a C(2)-stereogenic centre in (+)- 2 . The total synthesis of (−)-subersic acid 3 was carried out based on a Stille coupling between allyl trifluoroacetate congener 25c , derived from (8a R )- 7 , corresponding to the diterpene part, and aryl stannane congener 26 in the presence of Pd catalyst and CuI as an additive.

The carbonylative cyclization of 1,1-diethynyl acetates mediated by Phbox/Pd(TFA) 2 afforded a functionalized 4-cyclopentene-1,3-dione as a major product. In the absence of box ligand, a methoxycarbonylated orthoester was obtained predominantly.

In recent years, to meet demands for high efficiency, the use of concentrated winding motors, in which the coil is wound around every magnetic pole tooth, has increased. By using a separate core structure, the coil fill factor of the motor, and the motor efficiency per unit volume, are improved. However, since the assembly error is large compared with non-separate cores, a separate core can produce an imbalance in the flux distribution during motor rotation and cause cogging torque to increase. Usually the core assembly precision is determined by the circularity of inner core, however, it is difficult to predict the cogging torque of a separate core from its circularity because the circularity does not correlate well with the cogging torque.So, in this paper, with reference to the inner core shape, one or several points of deformation were intentionally introduced and the relationship with cogging torque was investigated. Consequently, it became clear that cogging torque caused by the inner core shape is the main component of cogging torque. Moreover, it turned out that cogging torque when there were several points of deformation was the vector sum of the cogging torque resulting from each one. From these results, a new evaluation method which predicts the cogging torque more precisely than evaluation using the circularity of inner core has been established. Furthermore, a new core, which we call a “joint-lapped core” is proposed as a core structure which can reduce cogging torque. Because the joint-lapped core was made by a press, similar to a conventional cylindrical core, the circularity and the cogging torque of the joint-lapped core were the same grade as non-separate cores.

A convergent synthesis of cystothiazoles C 1 and D 3 was achieved based on Julia coupling between the functionalized aldehyde 5b, corresponding to left half of the final molecule, and aryl sulfone 6 or 7, bearing a bithiazole moiety, corresponding to right half. Methylation of 1 and 3 gave cystothiazole A 2 and melithiazol B 4, respectively. The overall yield (5 steps from (2R,3S)-3-methylpent-4-yne-1,2-diol 10; 57%) of 5b via the present route was improved in comparison to that of the previously reported functionalized aldehyde 5a (7 steps from 10; 13%). By applying the modified Julia coupling method, selectivity (6E/6Z=20 : 1-26 : 1) toward the (6E)-form of the coupled products (15 or 19) against the corresponding (6Z)-form was improved in comparison to the Wittig method (6E/6Z=4 : 1-6.9 : 1).

This review summarizes the chemoenzymatic syntheses of biologically active natural products based on a combination of chemical diastereoselectivity and enzymatic enantioselectivity using lipase. Both primary alcohols possessing a chiral center at β-position of hydroxyl group and secondary alcohols were subjected to the lipase-assisted acylation in the presence of acyl donor to afford the optically active esters and the optically active alcohols corresponding to the starting material. These optically active compounds were converted to the biologically active natural products such as bisabolane type sesquiterpenes, oudemansins, nikkomycins B and Z, chuangxinmycin, cystothiazoles and melithiazols possessing antifungal and cytotoxicic activities, inhibition of NADH oxidation, etc.

Palladium-catalyzed methoxycarbonylation of (−)-(2R,3S)-1-tert-butyldimethylsiloxy-3-methyl-2-methoxypenta-4-yne 9 derived from (2R,3S)-epoxy butanoate 5 gave the acetylenic ester 10, which was treated with MeOH in the presence of Bu3P to afford selectively (Z)-β-methoxy acrylate congener 11 in 86% yield. Treatment of (Z)-11 with 99.8% enrichment of CDCl3 followed by consecutive desilylation and oxidation afforded the left-half aldehyde (+)-2. The overall yield (10 steps from 5; 23%) of (+)-2 via the present route was improved in comparison to that (10 steps from 5; 10%) of the previously reported route. By applying the modified Julia's coupling method, selectivity (E/Z=14:1) of the (E)-form (cystothiazole A 1) against the (Z)-form was improved in comparison to the Wittig method (E/Z=4:1 to 6.9:1).

The oxidative cyclization–carbonylation of meso-2-alkyl-2-propargylcyclohexane-1,3-diols mediated by Pd(II) with chiral bisoxazoline (box ligand) afforded bicyclic-β-alkoxyacrylates. Based on a ligand screening, 2,2′-isopropylidenebis[(4S,5R)-4,5-di(2-naphthyl)-2-oxazoline] ligand has been developed. The products with a chiral quaternary carbon were obtained in 71–100% yields with 85–95% ee.

rac-Hept-1-en-3-ol 4 was subjected to an enantioselective esterification in the presence of Novozyme 435 and vinyl crotonate as the acyl donor to give (3S)-oct-1-en-3-yl crotonate 7 in >99% ee and (3R)-alcohol 4 in 99% ee. The E-value of this enzymatic reaction was found to be >1000. The (S)-crotonic ester 7 was converted by ring-closing metathesis (RCM) using Grubbs’ catalyst to give (S)-oct-2-en-4-olide 1 in 96% yield while keeping the high enantiomeric excess.

Chiral enolate derived from (4R)-4-tert-butyldiphenylsilyloxymethyl-4-butanolide 10 with lithium hexamethyldisilyazide (LiHMDS) was treated with trisyl azide, followed by addition of TMSCl to give (2S,4R)-2-azido-4-[(tert-butyldiphenylsilyloxy)methyl]-4-butanolide 8 (53%), from which the first total synthesis of polyoxin M (1) was achieved in overall 3.2% yield (13 steps) from d -glutamic acid. Moreover, the synthesis of the reported synthetic intermediate (2S,4R)-4-hydroxyornithine congener 6 for biphenomycins A and B was also achieved in overall 4.1% yield (12 steps) from d -glutamic acid.

A stereoselective synthesis of a versatile chiral synthon possessing two stereogenic centers, (2 S ,3 S )-3-[2-(5-benzyloxypyridyl)]-2-methyl-1,3-propane diol 12 (>99% ee), was achieved by using a chemo-enzymatic method. The conversion of (2 S ,3 S )- 12 to the homochiral intermediate (2 S ,3 S ,4 S )-2-benzyloxycarbonylamino-4-[2-(5-benzyloxypyridyl)]-4- tert -butyldimethylsilyloxy-3-methylbutanoic acid 2 corresponding to the N-terminal amino acid congener of nikkomycin Z 1 is described.

For the purpose of the production of expensive perfume such as ambrein, ( S )- and ( R )-γ-cyclogeraniols ( 2 ) seem to be the important chiral synthons for the synthesis of ambrein The lipase QL from Alcaligenes sp.-catalyzed enantioselective acetylation of the (±)-(1,2)- trans -6,6-dimethyl-2-hydroxyhexane-1-carboxylate ( 9 ) was carried out and an alcohol (1 S , 2 S )- 9 and an acetate (1 R , 2 R )- 10 possessing high enantiomeric excess (>99% ee), respectively, were obtained. Both the alcohol (1 S , 2 S )- 9 and the acetate (1 R , 2 R )- 10 were converted to the ( S )- and ( R )-γ-cyclogeraniols ( 2 ), respectively.

The oxidative cyclization–carbonylation of propargylic esters mediated by Pd(II) afforded cyclic orthoesters, which were hydrolyzed into γ-acetoxy-β-ketoesters. Based on the NMR experiments, it was presumed that the cyclization reaction was initiated by a nucleophilic attack of carbonyl oxygen to the alkyne carbon coordinated to palladium(II). When the γ-acetoxy-β-ketoesters were treated with a basic condition, Knoevenagel–Claisen type condensation took place, and spiro furanone derivatives were obtained in good yields. We applied these reactions to steroid derivatives, and steroid derivatives having a spiro furanone fragment were synthesized. Among them, the spiro furanone 4j had vasorelaxant and bradycardiac activities. Compounds 2i–4k had inhibitory effect on CYP3A.

Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpenta-4-yne-1,2-diol (8) derived from the (2R,3S)-epoxybutanoate 7 followed by methylation gave the tetrahydro-2-furylidene acetate (–)-9, which was converted into the left-half aldehyde (+)-4. A Wittig reaction between (+)-4 and the phosphoranylide derived from the bithiazole-type phosphonium iodide 5 using lithium bis(trimethylsilyl)amide afforded (+)-(4R,5S)-melithiazol F (1), whose spectroscopic data were identical with those of the natural product 1. Moreover, the synthesis of (+)-(4R,5S)-melithiazol I (2), was achieved by the same synthetic strategy as that of (+)-(4R,5S)-melithiazol F (1). The antifungal activity of the synthetic melithiazols F (1) and I (2) against the phytopathogenic fungus, Phytophthora capsici, was evaluated by using a paper disc assay method.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Formal synthesis of tautomycin, which inhibits type 1 and type 2A protein phosphatases, was achieved. Spiroketal diol 21 was synthesized from alcohol 2 or 11 . The regioselective enzymatic acetylation of 21 with the lipase ‘Amano PS’ gave monoacetate 23 in 90% yield, which was converted into Ichihara's intermediate 31 based on Julia coupling and Wittig homologation.

Direct beta-glucosidation between (-)-myrtenol and nerol and D-glucose (3) using the immobilized beta-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave myrtenyl O-beta-D-glucoside (4) and neryl O-beta-D-glucoside (10), respectively. The coupling of the myrtenyl or neryl O-beta-D-glucopyranoside congeners (7 or 13) and 2,3,4-tri-O-benzoyl-beta-L-arabinopyranosyl bromide (8) afforded the coupled products (9 or 14), respectively. Deprotection of the coupled products (9 or 14) afforded the synthetic myrtenyl 6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside (Sacranoside A, 1) or neryl 6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside (Sacranoside B, 2), respectively.

This article discusses motors for compressors in domestic air conditioners, an area in which there is a strong demand for high efficiency and also reports the results of the efficiency improvement and productivity of a new core structure. An innovative core structure and manufacturing method boosts efficiency of permanent-magnet motors. This article presents the close relationship between the motor characteristics and the manufacturing method and indicates a way to improve both motor characteristics and the productivity. To pursue further improvement in motor performance by improving the coil space factor further using the joint-lapped core and manufacturing cores with smaller magnetic resistance.

Palladium(II)-catalyzed carbon–carbon bond formation between allyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside (3) and arylboronic acid congeners gave the corresponding cinnamyl 2,3,4,6-tetra-O-acetyl- β-d-glucopyranosides (4a–m) in good yield. Among them, coupling products 4a–m were converted to not only the naturally occurring phenylpropenoid β-d-glucopyranoside analogues (1a–e) but also the unnaturally ones (1f–m).

The Rosavin framework could be constructed with either phenylboronic acids, the protected arabinopyranosyl bromide 4 or the protected xylopyranosyl bromide 5 , along with allyl O -β- d -glucopyranoside 7 that could be easily prepared based on direct β-glucosidation between allyl alcohol and d -glucose using the immobilized β-glucosidase (EC 3.2.1.21). The key reaction was the Pd(II)-catalyzed Mizoroki-Heck type reaction between allyl β- d -glucopyranoside congeners 9 or 10 and arylboronic acids. Deprotection of the coupling products afforded synthetic Rosavin 1 , 4-methoxycinnamyl 6- O -(α- l -arabinopyranosyl)-β- d -glucopyranoside 2 , and cinnamyl 6- O -(β- d -xylopyranosyl)-β- d -glucopyranoside 3 , which were identical with the natural products in respect to the specific rotation and spectral data.

The deterioration mechanism of the storage characteristics of nickel-metal hydride batteries for hybrid electric vehicles (HEVs) has been investigated. The deterioration in the storage characteristics during charge–discharge cycling is caused by the microscopic short circuit in the separator which is influenced by the deposits from the positive and negative electrode elements such as zinc, cobalt and manganese. Based on the elucidated deterioration mechanism, the deterioration in the storage characteristics of nickel-metal hydride batteries was suppressed by employing a hydrogen-absorbing alloy with higher oxidation resistance for the negative electrode.

The lipase PL-266 from Alcaligenes sp. catalyzed enantioselective acetylation of the decahydro-5,5,8a-trimethyl-2-oxo-naphthalene-1-methanol-2-ethylene acetal (±)-6 was carried out and an acetate (8aS)-7 and an alcohol (8aR)-6 possessing high enantiomeric excess (>98% ee), respectively, were obtained. Both (8aS)-7 and (8aR)-6 were converted to the (8aS)- and (8aR)-decahydro-5,5,8a-trimethyl-2-oxo-naphthalene-1-carboxylates (4), respectively. The (8aR)-β-keto ester (4) was converted to the important intermediate (8aR)-16 for the synthesis of natural hyatellaquinone (3).

Dynamical properties of the three polymorphic phases α, β′ and β of tristearin [C3H5(OCOC17H35)3] have been studied by incoherent quasi-elastic neutron scattering and X-ray diffraction. At 293 K the difference in the lateral packing density of hydrocarbon chains significantly affected the mean square displacement 〈 U 2 〉 . As compared with β, an increase by 4% in the cross-sectional area for β′ resulted in a twofold increase in 〈 U 2 〉 . In case of α, an increase by 7% led to a threefold increase in 〈 U 2 〉 . The molecular motion in the α phase was analyzed using the model of the uniaxial rotational diffusion in a onefold cosine potential. It has been clarified that the rotational fluctuation about the chain axis in the α phase is rather restricted compared with that in the rotator phase of n-alkanes. The 〈 U 2 〉 in the α phase decreased significantly with the temperature, and reached the level of the 〈 U 2 〉 in the β phase at 193 K.

Direct beta-glucosidation between benzyl alcohol and D-glucose (5) using the immobilized beta-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave a benzyl beta-D-glucoside (1) in 53% yield. The coupling of the benzyl beta-D-glucopyranoside congener (8) derived from 1 with phenyl 2,3,4-tri-O-acetyl-1-thio-beta-D-xylopyranoside (9), ethyl 2,3,4-tri-O-acetyl-1-thio-alpha-L-rhamnopyranoside (13), and 2,3,4-tri-O-acetyl-alpha-L-arabinopyranosyl bromide (15) afforded 10, 14, and 16, respectively, as coupled products. Deprotection of 10, 14, and 16 provided the synthetic benzyl beta-D-xylopyranosyl-(1--6)-beta-D-glucopyranoside (2), benzyl alpha-L-rhamnopyranosyl-(1--6)-beta-D-glucopyranoside (3), and benzyl alpha-L-arabinopyranosyl-(1--6)-beta-D-glucopyranoside (4), respectively.

For the purpose of the direct characterization of the intact conjugated form in the urine of a methamphetamine (MA) abuser, 4-hydroxymethamphetamine (4-OHMA) glucuronate, corresponding to one of the metabolites of MA, was synthesized from the commercially available methyl 4-hydroxyphenylacetate.

Lipase-meditated separation of six hardly separable mixtures of structural isomers was carried out. It has become apparent that the hydrolysis rate of the C(5)-acetoxyl group of methyl (±)-5-acetoxy-4-aryl-(2E)-pentenoate possessing the ortho-substituents in the aromatic ring was slower than that of the corresponding compound with no substituents at the ortho-position. The hydrolysis rate of the C(5)-acetoxyl group of methyl (±)-5-acetoxy-2-aryl-(3E)-pentenoate possessing a remote reaction site from the ortho-substituents in the aromatic ring was proved to be faster than that of methyl (±)-5-acetoxy-4-aryl-(2E)-pentenoate.