DMAP-organocatalyzed O-silyl-O-(or C-)-benzoyl interconversions by means of benzoyl fluoride

Article abstract of DOI:10.1055/s-2007-968028

A mild and efficient transprotection of alcohols from silyl ethers 1a-f to benzoates 2a-f is reported in fair to good yields (50-98%). This silyl-acyl exchange reaction proceeds readily in acetonitrile at room temperature in the presence of benzoyl fluoride and DMAP as an acyl transfer catalyst. A two-step 'one-pot' DMAP-catalyzed silylcyanation-transprotection sequence which gives the corresponding O-benzoyl cyanohydrines 2g-l in high yields (72-98%) from various benzaldehyde and ketone derivatives is also reported. This original organocatalytic acyl transfer process was also found to be effective in the O-benzoylation of trimethysilyl enolates 1m-o, providing enol esters 2m-o. Lastly, the potential of this strategy is also illustrated by a DMAP-mediated Claisen condensation between ketene silyl acetals 1p-r and benzoyl fluoride. Georg Thieme Verlag Stuttgart.