74552-62-8

Reported herein is an ortho-oxygenative 1,2-difunctionalization of diarylalkynes under merged gold/organophotoredox catalysis to access highly functionalized 2-(2-hydroxyaryl)-2-alkoxy-1-arylethan-1-ones. Detailed mechanistic studies suggested a relay process, initiating with gold-catalyzed hydroalkoxylation of alkynes, to generate enol-ether followed by a key formal [4+2]-cycloaddition reaction. The successful application of the present methodology was also shown for the synthesis of benzofurans.

Diethyl 1-(trimethylsiloxy)-1-phenylmethanephosphonate carbanion 2 is introduced as a novel acyl anion equivalent.When 2 reacts with aldehydes or ketones, a 1,4 oxygen-oxygen silicon migration with subsequent loss of diethyl lithium phosphite is observed.An efficient method utilizing 2 for the preparation of otherwise difficultly obtainable substituted benzoins is presented.Also a novel one-pot method which offers a facile entry into the 2-phenylbenzofuran ring system from 2 via benzoin intermediates using hydriodic acid was developed.