Reaction of dibenzophospholes with benzoyl chloride; ring expansion to dibenzo[b,d]phosphorins
Abstract
5-Substituted dibenzophospholes (I; R = Ph, Me, Et, or Pri), on treatment with benzoyl chloride in the presence of triethylamine, followed by hydrolysis, undergo ring expansion to form 5,6-dihydrodibenzo[b,d]phosphorin 5-oxides (XI; R = Ph, Me, Et, or Pri) in high yield. 5-t-Butyldibenzophosphole (I; R = But) did not form an acylphosphonium salt on treatment with benzoyl chloride.