Synthesis of (.+-.)-Combretastatin D-1 and Combretastatin D-2
作者:Scott D. Rychnovsky、Kooksang Hwang
DOI:10.1021/jo00097a052
日期:1994.9
(+/-)-Combretastatin D-1 was synthesized in 16 steps by way of its congener, combretastatin D-2. In the key step, the strained 15-membered lactone ring was formed using high-dilution Mitsunobu conditions in 89% yield. Saturated seco acid 4 was a much better substrate for the cyclization reaction than the unsaturated seco acid 3.
Synthesis and revised configuration of (+)-combretastatin D-1
作者:Scott D. Rychnovsky、Kooksang Hwang
DOI:10.1016/0040-4039(94)88391-2
日期:1994.11
(+)-CombretastatinD-1 was prepared with modest enantioselectivity by Jacobsen epoxidation of combretastatin D-2 acetate. The configuration of (+)-combretastatin was shown to be (3R,4S) based on precedent from the Jacobsen epoxidation, and an advanced Mosher ester analysis of a derivative. The stereochemistry of natural (−)-combretastatin should be corrected to (3S,4R).