Total syntheses of epothilones B and d

A convergent, total synthesis of epothilones B (2) and D (4) is described. The key steps are Normant coupling to establish the desired (Z)-stereochemistry at C12-C13, Wadsworth-Emmons olefination of methyl ketone 28 with the phosphonate ester 8, diastereoselective aldol condensation of aldehyde 5 with the enolate of keto acid derivatives to form the C6-C7 bond, selective deprotection of acid 52, and macrolactonization.     

Short and Stereoselective Syntheses of Pheromone Components of Aproaerema Modicella

Efficient syntheses of pheromone components of Aproaerema modicella starting from a common intermediate 7-octyn-1-ol is described.     

Practical Synthesis of Pheromone Components of Achaea Janata (Noctuidae)

A practical synthesis of pheromone components of Achaea janata utilising double alkylations on TosMIC as key steps has been achieved.     

Lewis acid-assisted olefin cross-metathesis reaction: an efficient approach for the synthesis of glycosidic-pyrroloquinolinone based novel building blocks of camptothecin and evaluation of their antitumor activity

A series of glycosidic-pyrroloquinolinone based novel building blocks of camptothecin (2a–g) were synthesized via Lewis acid-assisted olefin cross-metathesis reaction using Ti(OⁱPr)₄ 30 mol % and 10 mol % of Grubb’s second generation catalyst with good to excellent yields. Most of these compounds exhibited significant growth inhibitory effects on all the tested cancer cell lines and three compounds (2c, 2d and 2e) showed potent cytotoxic activity.     

The trimethylsilyl xylyl (TIX) ether: a useful protecting group for alcohols

A new protecting group for alcohols, the p-trimethylsilyl xylyl (TIX) group has been developed. The TIX group is used to protect various alcohols under acidic as well as basic conditions. The protected ethers thus formed had noteworthy chemoselectivity upon deprotection in the presence of other benzyl ethers and commonly used protecting groups. The stability of the TIX group towards various reagents has also been examined.     

Reductive olefination of aldehydes via chromium Brook rearrangement

[reaction: see text] The combination of CrCl(2) and silyl chlorides converts aryl and conjugated aldehydes into olefinic adducts in good to excellent yields. When constrained by structural features, the intermediate vic-diol can be isolated. Available data are consistent with a novel chromium Brook rearrangement.     

Potassium Dodecatungsto Cobaltate Trihydrate: A New Heterogeneous Catalyst for the Synthesis of Homoallylic Alcohols and Amines

A simple and efficient procedure has been developed for one-pot synthesis of homoallylic alcohols and amines in good to excellent yields using a variety of aldehydes, amines, and allyltributylstannane in the presence of a catalytic amount of potassium dodecatungsto cobaltate trihydrate (K₅CoW₁₂O₄₀ · 3H₂O) as a heterogeneous catalyst at room temperature. The catalyst exhibited remarkable reusability.     

Efficient,High-Yield Protocol for the One-Pot Synthesis of Benzopyran Derivatives Catalyzed by p-TSA in Aqueous Media

A short and simple synthesis of benzopyran derivatives was accomplished in good to excellent yields by the reaction of salicylaldehyde with 1,3-cyclohexanediones in aqueous media catalyzed by para-toluenesulfonic acid. The structures were established by spectroscopic data and further confirmed by x-ray analysis. In addition, water was chosen as a green solvent.     

3-O-Acyl triggered tandem Lewis acid catalyzed intramolecular cyclization of diacetone glucose derivatives to 5-O-acyl-3,6-anhydro-d-glucose

BF₃ mediated one-pot conversion of 3-O-acyl-d-glucose-1,2:5,6-diacetonide derivatives to 5-O-acyl-3,6-anhydro-d-glucose is described through a tandem selective intramolecular cyclization sequence.