REACTIONS OF TRIPHENYLPHOSPHINE WITH ALPHA-HALOBENZYL PHENYL KETONES AND WITH ALPHA-MESYLOXYBENZYL PHENYL KETONE

The reactions of α-bromobenzyl phenyl ketone (11) and α-chlorobenzyl phenyl ketone (14) with triphenylphosphine are described. Both enol phosphonium and ketophosphonium halides are formed in ratios dependent upon reaction conditions. The enol phosphonium halides are solvolyzed to deoxybenzoin (16) and converted into diphenylacetylene (17). Debromination of 11 to 16 occurs with triphenylphosphine in the presence of methanol. α-Mesyloxybenzyl phenyl ketone (19) reacts with triphenylphosphine to give only the α-ketophosphonium mesylate via displacement of mesylate ion. Probable mechanisms for the observed reactions and the relationships of these reactions to the reactions of other α-halo ketones with phosphines are discussed. © 1969, American Chemical Society. All rights reserved.