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Regioselective addition of 1,3-dioxolanes (I) and (VI) to electron-deficient olefins provides products (III) and (V) as formylation equivalents and compounds (VII) and (VIII) as acetylation equivalents.

Functionalized cyclopropyl ketones have been found to undergo facile reductive cyclopropane ring opening with samarium (II) diiodide in the presence of a proton source. These reactions were exceedingly rapid, taking place in most cases at −78°C under neutral conditions. An ester group substituted at the C2 position of the cyclopropane ring played an important role in the ring opening of cyclopropyl ketones.

Various alkyl aryl secondary alcohols reacted with N,N-dichloro-p-toluenesulfonamide (N,N-dichloramine-T) in CH3CN at 35 °C to give the corresponding α-chloro ketones in excellent yields under mild and neutral conditions.

Thioacetals and thioketals were readily cleaved to carbonyl compounds in excellent yields by treatment with t-butyl thionitrite at ca. 0°C in acetonitrile under mild conditions. The conversion of thioketals to the ketones appears to be initiated via nitrosation on two sulfur atoms of the thioketals, followed by intramolecular transfer of nitroso oxygen.

Tosylhydrazones of carbonyl compounds were found to be readily cleaved into the corresponding carbonyl compounds in good yields under the mild conditions by treatment with dimethyldioxirane which is generated in situ from the reaction of acetone with potassium peroxymonosulfate.

Thionitrites or thionitrates have been considered to be unstable However, bulky groups' thio-NOn such as t-butylthio-nitrites and -nitrates have been readily synthesized and found to be stable enough for the use of the useful organic syntheses as an excellent nitrosation and diazotization reagents under mild conditions. Direct conversion of amines to the corresponding halides in the presence of copper halides (II), fluorination of heterocyclic amines in the presence of sodium tetrafluoroborate, α- oximation of methylene groups in ketones, facile cleavage of C=N bond to ketones, and desulfurization of thioacetals and thioketals, and other useful organic syntheses are described.

Various sulfides 1 reacted with sulfuryl chloride in the presence of metal nitrates in acetonitrile under mild conditions to give the corresponding α-chloro sulfoxides 2 in good yields.

Arenesulfonic acids were found to react with dinitrogen tetraoxide at −40°C in tetrahydrofuran to form arenesulfonyl nitrites which showed excellent diazotizing ability for the reductive deaminations of arylamines to arenes in the presence of anhydrous copper(II) halides as catalysts.

The highly stereocontrolled enantioselective reduction of ketones in the presence of catalytic amounts of new chiral (S)-β-amino alcohols 1 and 2 with borane in THF at-78 o C process in high chemical and optical yields; secondary alcohols with the R-configuration are obtained in the presence of 1b, but secondary alcohols with the S-configuration are obtained in the presence of 2a

Asymmetric 1,3-dipolar cycloaddition of nitrile oxides to new chiral acrylamides ( 3a-c ) is reported to give the chiral Δ 2 -isoxazolines with the high diastereoselectivity (up to 95 : 5).

Electrophilic substitution of phenylselenenyl chloride at the 5-position of uracils in the presence of silver reagents, such as Ag2O, AgBF4, or CF3CO2Ag, afforded the corresponding 5-phenylselenenyluracils in excellent yields. 1,3-Dimethyl-5-phenylselenenyluracil(2a), 5-phenylselenenyl-(2′,3′,5′-tri-O-acetyl)uridine(2b), 5-phenylselenoxyl-1,3-dimethyluracil(3a) and 5-phenylselenoxyl-(2′,3′,5′-tri-O-acetyl)uridine(3b) were used for various transformations at C-5 or C-6 of pyrimidine bases via nucleophilic substitution, a free radical process, and a Michael-type addition utilizing the unique properties of organo-seleno groups located on C-5 of pyrimidine bases.

Tetrabutylammonium peroxydisulfate is turned out to be a good reagent for the conversion of N,N-dimethyl-hydrazones to ketones.

α-Bromoesters are converted to β-ketoesters by treatment with samarium diiodide via self condensation under the mild conditions. The reaction appears to be initiated via the formation of samariun diiodide ester enolate for the Reformatsky reation type.

Various pyrimidine bases reacted with diethyl malonate in the presence of manganese(III) acetate or Ce(NH4)2(NO3)6 to give 5-(bis(ethoxycarbonyl)acetoxymethyl) pyrimidine nucleosides or 5-(bis(ethoxycarbonyl)methoxymethyl)pyrimidine nucleosides in good yields, respectively.

Chiral hydrazones, synthesized from (S)-1-amino-2-methoxymethylindoline and aliphatic aldehydes, reacted with trimethylsilyl cyanide in the presence of diethylaluminium chloride in CH2Cl2 at −78 °C to give chiral α-hydrazinonitriles with high diastereoselectivity (up to 96% de).

A convenient procedure for preparation of the title compound of ≥99% ee starting from 1-(2,3-difluoro-6-nitrophenoxy)-2-propanone (3) is presented. The key reaction is the intramolecular cyclization reaction in the presence of zinc chloride.

2-Phenylpyridine 1a reacts with various terminal alkenes in the presence of a rhodium(I) complex catalyst to give the corresponding mono ortho-alkylated products 2a–i and doubly alkylated products 3a–b (9:1). The same reaction using 3-methyl-2-phenylpyridine 1b gives the mono alkylated products 2j–n exclusively under the same reaction conditions due to steric hindrance between the methyl group of the pyridine and the alkyl group of 2j–n.

Palladium charcoal catalyzed dehydrogenation of α-hydrazinonitriles has been found to give hydrazonoyl cyanides in the presence of cyclopentene in high yields, which was applied to the synthesis of 1H-pyrazole-4-carboxylates.

Isocyanates react with SmI2 and tert-butyl alcohol in the presence of HMPA to give thioformamides in excellent yields under mild conditions.

The reactions of organolithiums with the new chiral hydrazones derived from ( S )-indoline-2-carboxylic acid afforded chiral hydrazines with high diastereoselectivities (up to 99% de) and the present method was utilized for the preparation of high optically pure ( R )-coniine (94% ee).

α,β- Unsaturated ketones reacted with tetra-n-butylammonium peroxydisulfate in the presence of hydrogen peroxide and base in acetonitrile at 25 °C to give the corresponding epoxides in excellent yields. © 1997 Elsevier Science Ltd.

The oxidative decarboxylation of aryl, α, α-diaryl, or arylakylacetic acids has been achieved by a 2-nitrobenzenesulfonyl peroxy radical intermediate (I) generated by the reaction of 2-nitrobenzenesulfonyl chloride with potassium superoxide at −20°C in dry acetonitrile.

Various benzyl ethers react with a 2-nitrobenzenesulfonylperoxyl radical intermediate generated from 2-nitrobenzenesulfonyl chloride and potassium superoxide at –25 °C in acetonitrile to give the corresponding esters in high yields.

Newly modified-echinomycin such as S-methylated sulfonium perchlorate of echinomycin (1), monosulfoxide (2), disulfoxid (3) and sulfone (4) have been prepared and evaluated for in vitro biological activities of cytotoxicity against P388, B16 and SNU-16 as well as in vivo antitumor activity against murine leukemia P388 and melanoma B16.

5-Phenyliodonium triflate substituted uracil nucleosides have been prepared by one step reaction of uracil nucleosides with (diacetoxyiodo)benzene-trifluoromethanesulfonic acid.

1,3,4-Thiadiazolines have been smoothly synthesized by a new stepwise cyclization of hydrazonoyl cyanides with isothiocyanates in the presence of NaH at 25°C.

Various aziridines reacted with N2O4 (2 eq) in the presence of Et3N (1 or 2 eq) in dry THF to give the corresponding ethylenes in good to excellent yields at (-23 °C or -43 °C) in 10 min under Ar.

5-Alkyl-2,4,6-trichloropyrimidines reacted with various nucleophiles to afford the regioselectively 6-substituted pyrimidines as the major products in good yields, which were transformed to 5-alkyl-6-arylmethyl-2,4-pyrimidinediones of a key intermediate of MKC-442.

Diels–Alder cycloadditions of chiral acrylamides with cyclopentadiene proceed with high diastereofacial selectivity, giving either endo-R to endo-S products depending of the Lewis acid used.

A variety of aromatic compounds substituted with an electron donating group such as methoxy, hydroxy, or amino group, were regioselectively iodinated with iodine in the presence of tetrabutylammonium peroxydisulfate under mild conditions in excellent yields.

Reaction of superoxide ion (O2 π? ) with o-nitrobenzenesulfonyl chloride yields a material with strong oxidizing ability, capable of oxidizing benzylic methylenes to the aryl ketones, benzylic ethers to benzoic esters, hydrazones to ketones, and electron deficient alkenes regioselectively to epoxides. The oxidizing species is tentatively assigned the o-nitrobenzenesulfonyl peroxy radical structure 1. Tetrabutylammonium hydrogen sulfate, on treatment with potassium persulfate under phase transfer conditions, gives tetrabutyl ammonium peroxydisulfate 2, a new oxidizing agent capable of oxidizing primary and secondary alcohols to the corresponding aldehydes and ketones in almost quantitative yields in aprotic solvents under anhydrous conditions; 2 is evidently a source of tetrabutylammonium sulfate radical 3. Further reactions include formation of the tetrahydropyranyl or tetrahydro- furanyl ether derivatives on reaction with alcohols, regioselective iodinations of anisyl derivatives, and a,b-unsaturated ketones or esters, nucleophilic epoxidations of a,b-unsaturated ketones, and an interesting addition of the 1,3-dioxolanyl group to electron deficient alkenes, including a conversion of 1-nitrocyclohexene into a masked a-formylcyclohexanone. Superoxide anion radical (O2 -∞ ) reacts as a base, an anion, and a radical, but in general is a very weak oxidizing agent. In an attempt to activate O2 -∞ , we have examined the reaction of such substrates as disulfides, sulfinyl chlorides and sulfonyl chlorides.o-Nitrobenzenesulfonyl chloride was found to be the best activator, specifically when reacted with O2 -∞ in MeCN at -308C to form a species probably having the structure 1, which is stable enough for organic syntheses at low temperature (Scheme 1) (1). In connection with the metabolic oxidation of thioamide drugs, O2 -∞ was previously shown to react with thioamides or thioureas in MeCN under reflux for a long reaction time giving the corresponding amides or ureas (up to 85%) (2). The sulfonylperoxy radical intermediate 1 shows much stronger oxidizing ability giving excellent yields of amides or ureas at -35 8C in the same reactions (Scheme 2) (3).

Cyclopropanations of glycals followed by Lewis acid-mediated glycosylations with 5-substituted uracils afforded 1′β-2′,3′-dideoxy-2′-bis(ethoxycarbonyl)methyluridine nucleosides in a highly regiospecific and stereoselective manner in good yields.

Diastereoselective and regioselective [1,5]-C,H insertion reactions of 2′-deoxy-3′-diazomalonate nucleosides afforded τ-butyrolactones of nucleosides as chiral synthons for the preparation of 2′-C-branched nucleosides.

α-Bromoacrylamides (1) reacted with aldehydes or ketones, in the presence of SmI2 at −78 °C in THF, within 5 min to produce Baylis–Hillman type reaction products (2) through an anionic process using vinylsamarium Grignard species in good yields (52–89%).

α-Bromocyclicacetals, α-bromocyclicketals and α-bromocyclicthioketals, derived from cyclic and acyclic ketones and aldehydes, reacted with samarium diiodide at −78°C in THF to furnish the corresponding enol ethers or thioenol ethers containing hydroxy or thiol moieties in high yields.

α-Keto amides bearing (S)-indoline chiral auxiliaries reacted with lithiated methoxyallene or lithium acetylides to produce the corresponding dihydrofuranones 7 through formation of the tertiary α-hydroxy allenes, or tertiary α-hydroxy acetylenes, respectively, at −78 °C with high diastereoselectivities (up to >99% de).