An enantioselectivetotalsynthesis of (+)-anthecularin, an antiplasmodial and antitrypanosomal sesquiterpene lactone, has been achieved in 3.9% overall yield through 18 steps from a known dibromo alcohol. The key features of the synthesis include an intramolecular Claisen-type cyclization of a formyl-protected hydroxyl lactone to construct a bicyclic intermediate with a quaternary stereogenic center
A mild, efficient, and highly regio- and stereoselective method for the methoxy and ethoxy bromination of olefins has been developed using NH4Br as a bromine source and Oxone as an oxidant. Various kinds of olefins (aromatic, linear, and cyclic olefins) afforded the corresponding alkoxy brominated products in moderate to excellent yields. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resources: Full experimental and spectral details.]
Thermal sigmatropic rearrangements of vinylallenes leading to 11-cis-retinoids and the novel properties of 9-cis,11-cis,13-cis-retinal and 11-cis,13-cis-retinal
作者:Christopher G. Knudsen、Roshantha A. S. Chandraratna、Leslie P. Walkeapaa、Yeshpal S. Chauhan、Stephen C. Carey、Thomas M. Cooper、Robert R. Birge、William H. Okamura
DOI:10.1021/ja00344a034
日期:1983.3
Stereochemistry of the carbon to carbon bond formation in the biosynthesis of polyprepenyl chains with Z double bonds. Studies with undecaprenyl-pyrophosphate synthetase