Reactions of phenanthrene-9,10-quinone with benzoyl- and acetylmethylenetriphenylphosphoranes. Trapping of the o-quinone methanide intermediates

Abstract

The reaction of phenanthrene-9,10-quinone (1) with the phosphorus ylide (2a) to give compounds (6a), (9a), (11), and (13) has been reinvestigated. Reaction of (1) with the phosphorus ylide (2b) afforded compounds (5b), (6b), and (9b). The transformations (5b)→(6b) and (6b)→(5b) have also been studied. When the reactions between (1) and the ylides (2a,b) were carried out in the presence of ethyl vinyl ether both the expected products (17a,b) and (18a,b) and the unexpected products (20a,b) were obtained by a trapping process.