A total synthesis of the styryllactone (+)-goniodiol from naphthalene.

Abstract

The cytotoxic natural product (+)-goniodiol was prepd. in twelve steps from enantiomerically pure cis-dihydrocatechol, which is readily obtained by microbial oxidn. of naphthalene. Elaboration of the cis-dihydrocatechol involves an initial oxidative cleavage to dialdehyde followed by redn. to give a diol. Conversion of the diol into an acetal required, inter alia, selective oxidn. of the benzylic alc. moiety followed by a metal-catalyzed decarbonylation of the resulting aldehyde. Allylation of I with allyltributylstannane in the presence of lithium perchlorate gave a ca. 2.7:1 mixt. of alcs., each of which was converted into the corresponding acrylate under std. conditions. Subjection of these ester derivs. to a ring-closing metathesis (RCM) reaction with Grubbs' first-generation catalyst gave the anticipated lactone II and its diastereomer. Acid-catalyzed removal of the acetonide protecting group within II then afforded (+)-goniodiol, while analogous deprotection of the congener afforded 6-epi-(+)-goniodiol.