Symmetry-Driven Synthesis of Indole Alkaloids: Asymmetric Total Syntheses of (+)-Yohimbine, (-)-Yohimbone, (-)-Yohimbane, and (+)-Alloyohimbane
摘要:
Total asymmetric syntheses of the target alkaloids are reported. The syntheses involve the preparation of enantiomerically pure (S,S)-1,3,3a,4,7,7a-hexahydro-2(H)-inden-2-one 7 and its meso isomer 5. Each ketone is then converted into a ring-expanded lactam using an oxaziridine synthesis/rearrangement protocol. The applications of Bischler-Napieralski ring constructions along with appropriate functional group transformations afford enantiomerically enriched alloyohimbane or yohimbane from the meso- or C-2-symmetric ketones, respectively. A cis-5,6-diacetoxy compound (18) derived from the (S,S)-ketone served as the starting material for the total syntheses of the more highly functionalized alkaloids. Accordingly, a site-specific insertion of the indole-containing side chain was accomplished via stereoselective formation of an oxaziridine followed by its stereospecific rearrangement. The selectivity of this sequence allowed for the differentiation of alcohols at C-17 and C-18 (yohimbine numbering) and the synthesis of Delta 18,19-yohimbone. This alpha,beta-unsaturated ketone was converted into either (-)-yohimbone or (+)-yohimbine using standard chemistry.
Total Synthesis of (−)-Mucosin and Revision of Structure
作者:Jens M. J. Nolsøe、Simen Antonsen、Carl H. Görbitz、Trond V. Hansen、Jannicke I. Nesman、Åsmund K. Røhr、Yngve H. Stenstrøm
DOI:10.1021/acs.joc.8b02318
日期:2018.12.21
The first totalsynthesis of (−)-mucosin (6), an unusual marine hydrindane natural product incorporating a prostaglandin-like submotif, has been achieved. As a result of the campaign, three of the four all-carbon stereocenters in the purported structure 1 have been revised. Of particular note is the excellent control over β-chirality in conjugate addition to ester (−)-22 and the facial selectivity
[EN] [6+5] FUSED BICYCLES AS A THROMBIN ANTAGONIST, PROCESS FOR PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITIONS CONTAINING THE BICYCLES<br/>[FR] BICYCLES FUSIONNÉS [6+5] EN TANT QU'ANTAGONISTES DE LA THROMBINE, PROCÉDÉ DE PRÉPARATION DE CEUX-CI ET COMPOSITIONS PHARMACEUTIQUES CONTENANT LES BICYCLES
申请人:KOREA RES INST CHEM TECH
公开号:WO2011162562A2
公开(公告)日:2011-12-29
The present invention relates to the new [6+5] fused bicycle derivatives, pharmaceutically acceptable salts or isomers thereof, processes for preparing the same, and pharmaceutical compositions comprising the same. The [6+5] fused bicycle derivatives can antagonize the thrombin receptor and thus may be effectively used for the treatment and prevention of thrombus, platelet aggregation, atherosclerosis, restenosis, blood coagulation, hypertension, arrhythmia, angina pectoris, heart failure, inflammation and cancer when used alone or with other cardiovascular agents.