Enantioselective total synthesis of altohyrtin C (spongistatin 2)
作者:David A. Evans、B.Wesley Trotter、Paul J. Coleman、Bernard Côté、Luiz Carlos Dias、Hemaka A. Rajapakse、Andrew N. Tyler
DOI:10.1016/s0040-4020(99)00438-x
日期:1999.7
The first total synthesis of a spongipyran macrolide, altohyrtin C, is described. The convergent synthesisstrategy relies on a regioselective macrolactonization, a stereoselective Wittig coupling of the two major synthetic fragments, a complex anti aldol reaction to join the C1–C15 and C16–C28 spiroketal regions, and an anomeric sulfone acylation to join the C29–C37 and C38–C43 pyran regions. The
Addition of allylstannanes to glycal epoxides. A diastereoselective approach to β-C-glycosidation
作者:David A. Evans、B. Wesley Trotter、Bernard Côté
DOI:10.1016/s0040-4039(98)00138-5
日期:1998.3
A new method for the synthesis of beta-C-allyl glycosides has been developed for use in the synthesis of the spongipyran macrolides. Functionalized dihydropyrans are transformed to cia tetrahydropyrans via a two step process: i) epoxidation using dimethyldioxirane and ii) Lewis acid mediated epoxide opening with allylstannanes as nucleophiles. This protocol, which can be successfully applied to complex systems, augments the limited body of methodology available for the preparation of beta-configured C-glycosides. (C) 1998 Elsevier Science Ltd. All rights reserved.