Arata Yasuda

Trifluoromethyl group induced highly stereoselective synthesis of α-hydroxy carbonyl compounds

Abstract The reaction of enolate prepared from ethyl 3-methyl-4,4,4-tri-fluorobutyrate with MoO5-Py-HMPA complex provides ethyl (2S★,3S★)-2-hydroxy-3-methyl-4,4,4-trifluorobutyrate predominantly. In contrast, NaBH4 reduction of the corresponding 2-oxobutyrate affords (2R★, 3S★)-hydroxyester preferentially.

SYNTHESIS OF 7-FLUORO-2,4-METHYLENE-17,20-DIMETHYLPROSTACYCLINS. NOVEL STABLE PROSTACYCLIN ANALOGS AS POTENT ANTI-ANGINAL AGENTS

Abstract Synthesis of new stable fluoroprostacyclins, 7-fluoro-2,4-methylene-17, 20-dimethylprostacyclins (1,2) with potent and long-lasting anti-anginal activities has been achieved. The cyclobutylene prostaglandin skeleton 10 was constructed efficiently according to three-component coupling reaction. Stereospecific fluorination of silyl ether 11 and subsequent cyclization of the fluoride 12 successfully provided the desired 7-fluoro-2,4-methylene-17,20-dimethylprostacyclin.

Synthesis of new stable fluoroprostacyclin analogs with potent anti-anginal activity

Abstract Synthesis of new stable fluoroprostacyclins, 7-fluoro-2,4-methylene-17,20-dimethylprostacyclins ( 1, 2 ) with potent and long-lasting anti-anginal activities has been achieved via three-component coupling reaction and stereospecific fluorination.

Titanium-promoted highly stereoselective synthesis of α,α-difluoro-β,γ-dihydroxyester. Simple route to 2-deoxy-2,2-difluororibose

Abstract The highly stereoselective synthesis of α,α-difluoro-β,γ-dihydroxyesters is described. Reformatsky reaction of bromo- or iododifluoroacetate with D-glyceraldehyde provided (3R, 4R)-2,2-difluoro-4,5-O-cyclohexylidene-3-triethylsiloxypentanoic acid ethyl ester in high yield, with more than 95% diastereoselectivity, by asymmetric induction promoted by Cp2TiCl2. The reaction affords a simple and practical route to 2-deoxy-2,2-difluororibose.

Synthesis of 6-Fluorodehydroepiandrosterone

Abstract A novel 6-fluorodehydroepiandrosterone was synthesized with dehydroepiandrosterone in 9 steps.