ADDITION OF GAMMA-METHOXY ALLYLSULFONYL ANIONS TO CYCLOPENTENYL PHENYL SULFONES - A FACILE SYNTHESIS OF BETA-CYCLOPENTENYL-SUBSTITUTED DIENONES AND TRIENONES

gamma-Methoxy allylsulfonyl anions undergo smooth conjugate addition t o mono- and bicyclic cyclopentyl sulfones. Hydrolysis of the intermedi ate abducts affords delta-sulfonyl-substituted enones which may be eli minated to dienyl ketones. The mechanism of this reaction is shown to involve the intermediacy of spiro-fused cyclopropyl sulfones conjugate d to an enol ether moiety. Exploration of the scope and limitations of this procedure demonstrates the potential for triply-convergent synth esis of tricyclic dienones via cyclization of a trienyl ketone.