Enynones in organic synthesis. 7. Substituent effects on the α-tocopherol-catalyzed cyclization of enynones to methylenecyclopentenones. Convenient syntheses of members of the methylenomycin class of antibiotics

Article abstract of DOI:10.1021/jo00097a036

Substituent effects on the α-tocopherol (vitamin E, 3b) catalyzed cyclization of a wide variety of enynones 1a-z to methylenecyclopentenones 7a-z have been examined, with particular emphasis given to electron-withdrawing and -donating groups at positions