SYNTHESES OF BETA , BETA -DIARYLVINYL PHENYL KETONES BY BENZOTRIAZOLE-MEDIATED TANDEM COUPLING-ELIMINATION

â,â-Diarylvinyl phenyl ketones are frequently observed in natural products and are widely used versatile organic synthons; for example, (i) they can be epoxidized1,2 and then converted into cumarones and flavones,2 (ii) they can be added to aromatics to give polyaryl substituted ketones,3 or (iii) they can be simply hydrogenated to give ketones.4 The most important synthesis of â,â-diarylvinyl phenyl ketones, direct aldol condensation, suffers limitations due to cross-coupling and Michael-type reactions, which cannot be always overcome by recent alternatives.5,6 The well-known acylation of olefins to such R,â-enones is frequently limited by the formation of numerous byproducts.7 Photodecarbonylation of aryl-substituted furanones affords â,â-diarylvinyl phenyl ketones in good yields.8,9 A recent comprehensive review10 confirms that additional general and versatile pathways to â,â-diarylvinyl phenyl ketones would be valuable. We now present a new benzotriazole-mediated route to â-substituted R,â-enones utilizing the corresponding diarylmethanols or diarylmethyl halides and R-bromoacetophenone.