Strongylodiols A, B and C, new cytotoxic acetylenic alcohols isolated from the Okinawan marine sponge of the genus Strongylophora as each enantiomeric mixture with a different ratio
Three newcytotoxic long-chain acetylenic alcohols, strongylodiols A, B and C, were isolated from the Okinawanmarinesponge of the genus Strongylophora. Their gross structures were elucidated based on spectroscopic analysis. During the process for determination of the absolute stereochemistry at C-6 using the modified Mosher's method, these acetylenic alcohols were each found to be an enantiomeric
(R)-strongylodiols C and D, with 99% ee were achieved. The key steps of the strategy include the zipper reaction of an alkyne, the asymmetric alkynylation of an unsaturated aliphatic aldehyde catalyzed with Trost’s ProPhenol ligand, and the Cadiot–Chodkiewicz cross-coupling reaction of a chiralpropargylicalcohol with a bromoalkyne.