described, starting from optically pure (S)-malic acid and methyl (R)-3-hydroxy-2-methylpropionate. The synthesis is highly convergent by coupling the three fragments C1-C6 (fragment D), C7-C10 (fragment C), and C11-C21 (fragment B). Key steps are two stereoselectiveWittig type olefinations to generate the 12,13- and 16,17-double bonds, an enantioselective Mukaiyama aldol addition to synthesize fragment
Total Synthesis of (−)-Spirangien A, an Antimitotic Polyketide Isolated from the Myxobacterium<i>Sorangium Cellulosum</i>
作者:Ian Paterson、Alison D. Findlay、Christian Noti
DOI:10.1002/asia.200800445
日期:2009.4.6
A stereocontrolled total synthesis of the cytotoxic spiroacetal‐containing polyketide (−)‐spirangien A is described. This utilizes an aldol‐based strategy to construct a common stereotetrad intermediate that was elaborated into the spiroacetal core, followed by the introduction of the unstable pentaene‐containing side chain, performed with exclusion of light, using sequential Stille cross‐coupling
Compound 11, representing the C(11)-C(20) segment of the macrolide epothilone B (1b) has been prepared using two Wittig reactions and a Sharpless asymmetric epoxidation as the key steps. (C) 1997 Elsevier Science Ltd.
Enantioselective Synthesis of (+)-(2<i>R</i>,3<i>S</i>,6<i>R</i>)-Decarestrictine L
作者:Guy Solladié、Eva Arce、Claude Bauder、M. Carmen Carreño
DOI:10.1021/jo972187r
日期:1998.4.1
A convergent enantioselective synthesis of (+)-(2R,3S,6R)-decarestrictine L (1), a natural inhibitor of cholesterol biosynthesis, is described from commercially available (S)-malic acid and (R)-isobutyl lactate. The third chiral center was created by stereoselective reduction of a chiral alpha-hydroxy ketone, and an intramolecular S(N)2-type reaction allowed the stereocontrolled formation of the tetrahydropyranyl ring.