Reduction of carbonyl compounds with trialkoxysilane can be readily catalyzed by alkoxides of alkali metal. A considerable high asymmetric induction takes place by use of optically active diolates or even N-lithio 2-amino alcoholates derived from optically active amino acid as a catalyst.
Preparation of a chiral building block based on 1,3-syn-diol using Pseudomonas fluorescens lipase and its application to the synthesis of a hunger modulator.
作者:Zhuo-Feng XIE、Kiyoshi SASAKI
DOI:10.1248/cpb.37.1650
日期:——
A novel, chiral building block (9) consisting of 1, 3-syn-diol was obtained by highly enantioselective hydrolysis of the meso-diacetate (8) with Pseudomonas fluorescens lipase (PFL), and (-)-9 was used to synthesize one of four possible stereoisomers of 2-hydroxy-4-hydroxymethyl-4-butanolide, which has hunger modulating activities.
Synthesis and the absolute configuration of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide as a new chiral building block for prostanoid synthesis
The synthesis of both enantiomers of 4,5-dihydroxy-3-(formyl)cyclopent-2-enone acetonide (5) was accomplished in five steps starting from meso-tartaric acid (6). The key steps involved are preparation of the isopropylidene protected 3-[(dimethoxyphosphoryl)methyl]-4,5-dihydroxycyclopent-2-enone (9), resolution of the diastereoisomeric products 10 of the Horner reaction of racemic 9 with (R)-glyceraldehyde
A novel route to a chiral building block for the preparation of cyclopentenyl carbocyclic nucleosides. Synthesis and anticancer activity of enantiomeric neplanocins A
The synthesis of both enantiomers of 3-[(tert-butyldimethylsilyl)oxy]methyl-4,5-O-isopropylidenecyclopent-2-en-1-ol was accomplished in six steps based on optically inactive dimethyl meso-tartrate. This key intermediate in the synthesis of cyclopentenyl carbocyclic nucleosides was subsequently applied in the preparation of enantiomeric neplanocins A. The toxic effect of these compounds was investigated
Efficient Synthesis of Enantiopure Conduritols by Ring-Closing Metathesis
作者:Morten Jørgensen、Erik H. Iversen、Andreas L. Paulsen、Robert Madsen
DOI:10.1021/jo0101297
日期:2001.6.1
to enantiopure conduritols are described starting from the chiral pool. In both cases, the cyclohexene ring is assembled via ring-closing olefin metathesis. The terminal diene precursers for the metathesis reaction are prepared either from octitols or from tartaric acids. The former route involves a new method for selective bromination of the primary positions in long-chain carbohydrate polyols. Subsequent