Stereoselective Syntheses of Rolliniastatin 1, Rollimembrin, and Membranacin
摘要:
A radical cyclization of beta-alkoxyvinyl sulfoxides-Pummerer rearrangement-allylation protocol was successfully applied to the synthesis of the threo/cis/threo/cis/erythro bis-oxolane moiety in rolliniastatin 1 (1), rollimembrin (2), and membranacin (3).
Total Synthesis of (+)-cis-Sylvaticin: Double Oxidative Cyclization Reactions Catalyzed by Osmium
摘要:
The double oxidative cyclization of dienes is a viable procedure for making complex natural products containing cis-THF units. A double deprotection/double oxidative cyclization strategy using catalytic osmium tetroxide was used to construct the bisheterocyclic core of cis-sylvaticin and ultimately confirm its structure. The natural product was then prepared by a short sequence of reactions that is exceptionally concise: the final route being just 13 linear steps and 19 chemical operations in total.
Concise Syntheses of the Natural Products (+)-Sylvaticin and (+)-<i>cis</i>-Sylvaticin
作者:Timothy J. Donohoe、Robert M. Harris、Oliver Williams、Gráinne C. Hargaden、Jeremy Burrows、Jeremy Parker
DOI:10.1021/ja9049959
日期:2009.9.9
Two concise syntheses of the natural products cis-sylvaticin and sylvaticin are reported, using oxidative cyclization methodology as the key step. A sequential solvolysis/hydride shift/intramolecular reduction cascade was used to establish the trans stereochemistry of one of the THF rings of sylvaticin.