Total Syntheses of 2,2‘-epi-Cytoskyrin A, Rugulosin, and the Alleged Structure of Rugulin
摘要:
The total syntheses of 2,2'-epi-cytoskyrin A, rugulosin, and the alleged structure of rugulin are described. These naturally occurring bisanthraquinones and their relatives are characterized by novel molecular architectures at the core, at which lies a more or less complete, cage-like structural motif termed "skyrane". The strategies developed for their total synthesis feature a cascade sequence called the "cytoskyrin cascade" and deliver these molecules in short order and in a stereoselective manner.
Simple, Efficient Chemoenzymatic Synthesis of (S)-5-(tert-Butyldimethylsilyloxy)-2-cyclohexenone and Enantiomeric Ketone Intermediates of 19-Nor-1α,25-dihydroxyvitamin D3
19-Nor-1 α,25-dihydroxyvitamin D3 (2) was synthesized from A-ring precursor 5 and ketone 4. Two synthesis of 5 were studied; one starting from (-)-quinic acid as a template and one starting from cis-1,3,5-cyclohexanetriol via a chemoenzymatic approach.
由A环前体5和酮4合成19-Nor-1α,25-dihydroxyvitamin D 3(2)。研究了5的两个合成;一种通过化学酶促方法以(-)-奎尼酸为模板,另一种以顺式1,3,5-环己三醇为模板。
Multiselective enzymatic reactions for the synthesis of protected homochiral cis- and trans-1,3,5-cyclohexanetriols
作者:Beat Wirz、Hans Iding、Hans Hilpert
DOI:10.1016/s0957-4166(00)00368-2
日期:2000.10
For the synthesis of the potentially antipsoriatric vitamin D derivative 3 (Ro 65-2299) an efficient and multiselective enzymatic step had been developed in which the easily accessible trans-1,3,5-triacetoxy-cyclohexane 5 was selectively monohydrolyzed excess (>99%) and yield (84%). Furthermore, for the synthesis of the enantiomer of 3, a simple and efficient enzymatic procedure for the asymmetric acetylation of cis-1,5-dihydroxy-3-(tert -butyldimethylsilanoxy)-cyclohexane 10 in an anhydrous organic solvent providing (1R,3S,5S)-1-acetoxy-3-hydroxy-5-(tert-butyldimethylsilanoxy)-cyclohexane 11 in >99% ee and quantitative yield is described. (C) 2000 Elsevier Science Ltd. All rights reserved.
A process for the preparation of beta-hydroxy-delta-lactone using novel intermediates
申请人:Council of Scientific & Industrial Research
公开号:EP1234884B1
公开(公告)日:2008-08-20
Total Synthesis of (+)-Rugulosin and (+)-2,2′-epi-Cytoskyrin A through Cascade Reactions
作者:K. C. Nicolaou、Yee Hwee Lim、Charles D. Papageorgiou、Jared L. Piper