Concise Syntheses of the Natural Products (+)-Sylvaticin and (+)-cis-Sylvaticin
摘要:
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.
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.
Asymmetric Total Synthesis of Trilobacin via Organoselenium-Mediated Oxonium Ion Formation/SiO<sub>2</sub>-Promoted Fragmentation
作者:Te-ik Sohn、Mi Jung Kim、Deukjoon Kim
DOI:10.1021/ja106116v
日期:2010.9.8
An asymmetric total synthesis of trilobacin (1), an annonaceous acetogenin with potent anticancer activities, was accomplished wherein the construction of its erythro-bis(2,2')-tetrahydrofuran core 2 featured a novel organoselenium-mediated oxoniumion formation/SiO(2)-promoted fragmentation of alpha,alpha'-cis-oxocene 3.