REGIOSPECIFIC AND HIGHLY STEREOSELECTIVE FORMATION OF BENZISOCHROMAN-6,9-QUINONES - SYNTHESIS OF (+/-)-VENTILAGONE AND (+/-)-VENTILOQUINONE-H

An approach known to give regiospecific cycloadditions over a wide range of substrates has been applied to the synthesis of (±)-ventilagone and (±)-ventiloquinone H using a novel, electron-rich heterocyclic diene. The strategy provides for the sole formation of the natural, thermodynamically less stable diastereoisomer. As a basis for comparison of the spectral data, (±)-ventilagone 7-methyl ether was equilibrated and hydrolyzed to a mixture containing (±)-isoventilagone, a prototype of the heretofore unidentified trans series of compounds. Convenient substrates for eventual access to the more highly substituted natural products have also been obtained. © 1990, American Chemical Society. All rights reserved.