ADDITION OF GAMMA-METHOXY ALLYLSULFONYL ANIONS TO CYCLOPENTENYL PHENYL SULFONES - A FACILE SYNTHESIS OF BETA-CYCLOPENTENYL-SUBSTITUTED DIENONES AND TRIENONES
Zd. Jin et Pl. Fuchs, ADDITION OF GAMMA-METHOXY ALLYLSULFONYL ANIONS TO CYCLOPENTENYL PHENYL SULFONES - A FACILE SYNTHESIS OF BETA-CYCLOPENTENYL-SUBSTITUTED DIENONES AND TRIENONES, Journal of the American Chemical Society, 117(11), 1995, pp. 3022-3028
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.