The first enantioselective total syntheses of pygmaeocinsB and C have been accomplished using an efficient and highly diastereoselective intramolecular Heck cyclization for the construction of a quaternary stereogenic center and the functionalized A-ring of the natural products as the key step.
New 20(10?5)abeo-Diterpenoids fromPygmaeopremna herbacea
作者:Qingchang Meng、Manfred Hesse
DOI:10.1002/hlca.19900730225
日期:1990.3.14
Two new 20(105)abeo-abietune diterpenoids, pygmaeooins B (1) and C (2), have been isolated from the roots of Pygmaeopremnaherbacea (Verbenaceae). Their structures were elucidated on the basis of spectroscopic data, and chemically, both compounds were correlated with each other. The absolute configurations were assigned tentatively on the basis of biogenetic pathway.