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The total synthesis of (+)-(I) was completed from 3-butyn-1-ol with an overall yield of 7% relying on regioselective epoxide opening, Sharpless asymmetric epoxidation, aldehyde-alkyne coupling, and ring-closing metathesis reactions as key steps.

The first stereoselective total synthesis of synparvolide C has been accomplished. An acid-catalyzed epoxide ring-opening reaction and ring-closing metathesis (RCM) were used for the cyclic ether and δ-lactone formation, respectively, to furnish the core structure of the target molecule. These reactions along with a succession of functional group manipulations led to the preparation of the natural product. The spectral and analytical data were used to establish the absolute configuration.

Lithium tetrafluoroborate efficiently catalyzes an unusual cyclization of o-hydroxybenzaldimines with 2,3-dihydrofuran and 3,4-dihydro-2H-pyran at ambient temperature to afford a class of new pyrano- and furanobenzopyran derivatives in excellent yields with high diastereoselectivity.

An approach to the asymmetric synthesis of fragments corresponding to C1C7 and C15C24 of (+)-discodermolide is reported. Key elements of the successful strategy include elaboration of two advanced fragments from a common precursor.

A wide variety of epoxides and aziridines were converted to the corresponding β-halohydrins and β-haloamines using cerium(III) chloride and the cerium(III) chloride/NaI system in acetonitrile. The reactions were highly regioselective and efficient with excellent yields under mild and neutral reaction conditions.

Intramolecular [4+2] cycloaddition reaction of aldimines derived from aromatic amines and O-allyl derivatives of salicylic aldehydes was efficiently catalyzed by BiCl3 to afford the corresponding tetrahydrochromano[4,3-b]quinolines in excellent yields. The products are isolated as 1:1 mixture of diastereoisomers.

The first stereoselective total synthesis of the natural cryptopyranmoscatone B1 has been accomplished from 3,4,6-tri-O-acetyl- d -glucal. In addition to the double cross-metathesis reaction, a tandem nucleophilic addition-diastereoselective reduction of an in situ generated oxocarbenium cation have been used as key steps to assemble the glycoside moiety of the target molecule.

The first total synthesis of a 10-membered macrolide, stagonolide E is described from readily available 4-penten-1-ol. The synthetic strategy involves Jacobsen's kinetic resolution, Sharpless epoxidation, Stille-Gennari, and Yamaguchi lactonization as key reactions.

The aza-Prins cyclization of homoallyl N-tosylamine with aliphatic aldehydes gives trans-2-alkyl-4-iodo-1-tosylpiperidines. This method is chemoselective as it works only with the aliphatic aldehydes, and, in the case of aromatic aldehydes, the starting materials are recovered.

The enantioselective total synthesis of (+)-patulolide C isolated from Penicillium urticae has been achieved from commercially available 9-decen-1-ol. Jacobsen’s kinetic resolution and sequential α-aminooxylation and Horner–Wadsworth–Emmons (HWE) olefination followed by Yamaguchi lactonization are used as the key reaction steps.

Asymmetric synthesis of putaminoxin, a phytotoxic macrolide from the cultured dinoflagellate Amphidinium sp., has been accomplished. Absolute configuration of putaminoxin was concluded to be 1 from comparison of the NMR data and [α] D values of synthetic and natural putaminoxin.

Clay catalyzed Friedlander condensation of 2-amino arylaldehyde or ketone with carbonyl compounds containing α-methylene group has been achieved in solvent free condition under microwave irradiation to give polycyclic quinoline derivatives.

Lithium Chloride is found to efficiently catalyse the acetylation of alcohols, thiols, phenols and amines with acetic anhydride in excellent yield.

A rapid and high yield preparation of half-esters from cyclic anhydrides using alcohols and Lewis acids is described.

A direct synthesis of pyrazolo[3,4-b]pyridines [5&6] and [l]benzopyrano[4′,3′-e]pyrazolo[3,4-b]pyridines (7) is described by Friedlander condensation. An alternative and a short route for the preparation of [l]benzopyrano[4′,3′-e]pyrazolo[3,4-b]pyridines (7) is also reported.

The total syntheses of (6R)-6-[(2R)-2-hydroxyhexyl]tetrahydro-2H-2-pyranone and 7-hydroxy-5-dodecanolide are described utilizing a Prins reaction and ring closing metathesis reaction sequence.

Aldoximes (1) can be rapidly converted into corresponding nitriles (2) in good yields with a novel reagent DBU under microwave irradiation.

The synthesis of 4-(-2-hydroxybenzoyl)pyrazoles (3) was achieved in a single step by the reaction of 3-formylchromones (1) with Phenylhydrazine or Tosylhydrazine under microwave irradiation without a solvent.

The total synthesis of (9S,12R,13S)-pinellic acid, a novel and potentially useful oral adjuvant, isolated from Pinelliae tuber has been accomplished.

A convenient reductive cleavage of 3-arylphthalides 1 into corresponding 2-benzylbenzoic acids and 2-(2-thienylmethyl)benzoic acid 2 by using iodotrimethyisilane is described.

Knoevenagel products 3 of 3-formylchromone (1) with isoxazol- 5-one 2, after reduction with NaBH4 and exposure to aqueous sodium nitrite/acetic acid and ferrous sulphate gave various benzopyranacetylenes 4 in good yield. IICT Communication No. 3850

A general synthetic approach has been developed for the first asymmetric total synthesis of tuberolactone 1, jasmine lactone 2 and δ-decalactone 3. The key step is the selective hydrogenation of triple and endocyclic double bonds in the key intermediate 4.

The title compound, C 24 H 29 NO 2 , is one of the intermediates of the potent HIV protease inhibitor Indinavir. The oxazolidine ring adopts an envelope conformation. The orientation of the benzyl groups facilitates C-H ··· π interactions, forming molecular chains along the a axis.

A novel and efficient one-pot synthesis of lactones (pyranones) has been achieved by domino Knoevenagel/hetero-Diels-Alder/elimination reactions of O- and N-prenyl aldehyde derivatives with Meldrum's acid in the presence of L- or D,L-proline. The reaction proceeds cleanly at room temperature to afford cis- or trans-fused products in good yields with high diastereoselectivity.

Synthesis of the C1–C25 ABC spiroketal ring system of spirastrellolides B and F has been executed. The synthetic strategy relied on radical cyclization, HWE olefination, (BDP)CuH conjugate reduction and spiro acetalization reactions.

A novel and green approach has been described for the synthesis of 2,3-dihydro-1H-1,5-benzodiazepines from o-phenylenediamines and ketones using cerium(III) chloride/sodium iodide supported on silica gel under mild and heterogeneous conditions. The reactions are carried out at room temperature without using any organic solvent.

A highly selective and efficient protocol has been developed for detritylation using 5 mol% BiCl 3 in acetonitrile. The cleavage proceeds at room temperature in high yields and the conditions are mild enough to tolerate avariety of acid-base sensitive functional groups.

Correction for ‘Metal-free C–N bond formations: one-pot synthesis of pyrido[2′,1′:2,3]imidazo[4,5-c]cinnolines, benzo[4′,5′]thiazolo- and thiazolo[2′,3′:2,3]imidazo[4,5-c]cinnolines’ by Satheeshkumar Reddy Kandimalla et al., RSC Adv., 2016, 6, 67086–67095.

The three component condensation of an aldehyde, a β-keto ester and urea (thiourea) in the presence of a catalytic amount of VCl 3 is disclosed for the solution phase synthesis of dihydropyrimidinones. The ease of synthesis and work-up allowed the parallel synthesis of a 48-membered library of dihydropyrimidinones quickly and efficiently in good yields.

FD-891, a structurally unique 16-membered macrolide having anticancer activity, was synthesized according to a strategy employing asymmetric allylation, Prins cyclization, cross-metathesis reaction, Yamaguchi lactonization, and Julia–Kocienski olefination.

A Pd-catalyzed sequential isomerization and reduction of primary propargylic alcohols affords the corresponding saturated aldehydes.

The Pd-catalyzed isomerization of allylic alcohols to aldehydes and subsequent addition of Wittig ylides gives α,β-unsaturated carbonyl compounds in one pot.

A convenient method for the preparation and cleavage of 1,1-diacetates of aldehydes is reported using AlCl 3 as catalyst.

BiCl3 efficiently catalyzed the intramolecular hetero-Diels–Alder reactions of aldimines generated in situ from aromatic amines and the N-allyl derivative of o-aminobenzaldehyde in refluxing acetonitrile to afford a novel class of hexahydrodibenzo[b,h][1,6]naphthyridine derivatives. The products are isolated as mixtures of trans and cis diastereoisomers in a 1:1 ratio, in good to excellent yields.

A variety of N-tosylaziridines undergo ring opening with pyrrole, furan, thiophene and indole in the presence of a catalytic amount of indium trichloride at ambient temperature to afford the corresponding β-aminoheterocycles in good yields with high regioselectivity.

Indoles react smoothly with terminal epoxides in the presence of catalytic amount of InCl 3 under mild conditions to afford the corresponding 3-alkyl indole derivatives in high yields with high regioselectivity.

Title compounds (IV) and (VI) are synthesized via a Sakurai—Prins—Ritter reaction sequence with high diastereoselectivity.

Title compound (VI) is synthesized using an iterative acetylene-epoxide coupling [ (III)] and a Yamaguchi lactonization as the key steps.

The Pd-catalyzed isomerization of primary allylic alcohols into the corresponding saturated aldehydes has been achieved at room temperature for the first time in good to excellent yields under mild conditions. The functional group compatibility in this reaction is studied, and this new methodology has been successfully applied in the synthesis of a C5−C13 tetrahydropyran ring system of (−)-brevisamide in seven steps.

Bismuth(III) chloride was found to be an efficient catalyst for the transesterification of a variety of β-keto esters with a wide range of alcohols to afford transesterified products in good to high yields in short reaction times (see Table).

Synthesis of stereoisomers of 6′-mono- and 4′,6′-di-O-benzyl cryptofolione is described through a key intermediate 6, which was prepared by coupling of iodobenzene 8 with chiral propargyl alcohol 9 under Cosford protocol conditions. Monobenzyl ether 4 is obtained via epoxide 6 opening with vinyl Grignard, followed by cross-metathesis reaction with a vinyl lactone 11. Whereas, dibenzyl ether 5 is prepared by epoxide 6 opening with chiral propargyl alcohol 7 followed by simple transformations and finally cis-Wittig olefination.

Homoallyl-N-tosylamine (I) reacts with aliphatic aldehydes to produce the title compounds with high trans-selectivity.

Pyrroles undergo conjugate addition with electron deficient olefins in the presence of a catalytic amount of indium trichloride at ambient temperature to afford the corresponding Michael adducts in excellent yields with high selectivity without polymerisation.

[structure: see text]. A highly selective cleavage of MEM ethers has been achieved in high yields using CeCl3.7H2O in refluxing acetonitrile under mild and neutral reaction conditions. The method is very rapid and compatible with other hydroxyl protecting groups such as Bn, TBDPS, Ac, Me, Tr, PMB, benzylidene, THP, MOM, BOM, and NHAc present in the substrate.

A variety of spirolactones are prepared from cyclic anhydrides via indium-mediated allylation and ring-closing olefin metathesis (RCM) reaction as key steps.

Advantages of this method are its generality, short reaction time, easy workup, and ease of recovery and reuse of the catalyst.