SYNTHESIS OF PROSTAGLANDINS BY CONJUGATE ADDITION AND ALKYLATION OF A DIRECTED ENOLATE ION - 4,5-ALLENYL PROSTAGLANDINS

Over the previous two decades many elegant syntheses of prostaglandins, which in the more sophisticated forms, allow the stereospecific introduction of the various asymmetric carbons have been accomplished. However, among these approaches the cuprate addition/enolate alkylation of a suitable cyclopentenone2 stands out because of brevity and convergence. The recent reports by Noyori3 and Co-rey4 and their colleagues have reduced to practice the conversion of 4-alkoxycyclopentenones to prostaglandin E2(PGE2) by conjugate addition of an organocopper derivative of the lower side chain followed by alkylation of the resulting carbanion with methyl 7-halohept-2-enoate5. © 1990, American Chemical Society. All rights reserved.