[2 3]Cyclophanetrienes from Wittig Reactions and Titanium-mediated Reductive Coupling.

Abstract

A series of new [2.2.2]cyclophanetrienes I (X = X1 = o-C6H4, p-C6H4; X1 = p-C6H4) and ferrocenophene II were prepd. by a threefold Wittig reaction of Br-P+Ph3CH2C6H4CHO-m or by twofold Wittig reactions followed by Ti-mediated reductive couplings of dialdehydes. The ferrocenophane II, in which the two 5-membered rings are linked by a conjugated p-system, has 2 mirror image forms with opposite helicity by 1H NMR. [on SciFinder (R)]