Catalytic Asymmetric Allylation Reactions Using BITIP Catalysis and 2-Substituted Allylstannanes as Surrogates for β-Keto Ester Dianions
作者:Gary E. Keck、Tao Yu
DOI:10.1021/ol990603j
日期:1999.7.1
text] Catalytic asymmetric allylation (CAA) reactions using the indicated allylstannane and the BITIP catalysts previously described by us give high yields and enantioselectivities in additions to aldehydes. The products are convertible to beta-keto esters by oxidative cleavage of the olefin. These reactions thus provide a useful catalytic enantioselective method for chain extension with introduction
Total Synthesis of Epothilones B and D: Stannane Equivalents for β-Keto Ester Dianions
作者:Gary E. Keck、Robert L. Giles、Victor J. Cee、Carrie A. Wager、Tao Yu、Matthew B. Kraft
DOI:10.1021/jo802215v
日期:2008.12.19
Studies leading to a total synthesis of epothilones B and D are described. The overall synthetic plan was based on late-stage fragmentassembly of two segments representing C(1)-C(9) and C(10)-C(21) of the structure. The C(1)-C(9) fragment was prepared by elaboration of commercially available (2R)-3-hydroxy-2-methylpropanoate at both ends of the three-carbon unit. Introduction of carbons 1-4 containing