Tetraphenylbutadienes via (1,1-Diphenylallyl)lithium.

Methods for the preparation of unsymmetrically substituted tetraphenylbutadienes (TPBs) have been investigated. A direct approach which capitalizes on the inherent acidity of 1,1-phenylpropylene appeared to be most feasible. The reaction involves stoichiometric (1:1:1) quantities of diarylpropene, n-butyllithium, and substituted benzophenone. Even though the product yield may be as low as 25-35%, this procedure is so straightforward that it is the method of choice. The use of a 2-fold excess of n-butyllithium was found to increase some product yields, but it is not yet known if this will increase production of all TPBs. 19 references, 1 table.