A stereoselective synthesis of potent cytotoxic macrolides, 11-alpha-methoxycurvularin and 11-beta-methoxycurvularin has been accomplished. The synthesis entailed Maruoka asymmetric allylation to introduce the stereocentres at C-11 and the key fragment was installed by using Grubbs cross-metathesis followed by CBS-reduction. (C) 2009 Published by Elsevier Ltd.
[4 + 2]-Annulations of Chiral Organosilanes: Application to the Total Synthesis of Leucascandrolide A
作者:Qibin Su、Les A. Dakin、James S. Panek
DOI:10.1021/jo0610412
日期:2007.1.1
Complete details of an asymmetric synthesis of leucascandrolide A (1) are described. The synthesis highlights the use of two diastereoselective [4 + 2]-annulations for the assembly of the functionalized bispyranyl macrolide 3. An efficient assembly and union of the oxazole-containing side chain 4 with macrolide 3 was carried out using a Mitsunobu reaction. A convergent route to the oxazole side chain