REACTION OF SILYL ENOL ETHERS WITH ARENEDIAZONIUM SALTS .1. ALPHA-ARYLATION OF KETONES

alpha-arylation of ketones is accomplished by the use of arenediazonium salts as aryl-cation equivalents. The reaction of silyl enol ethers with arenediazonium tetrafluoroborates proceeds in the presence of palladium(o) catalysts and tetraphenylborate anion to give alpha-aryl ketones in moderate-yields. Alternatively. silyl enol ethers smoothly react With arenediazonium tetrafluoroborates in pyridine even Without palladium catalysts and tetraphenylborate anion. affording arylated ketones in good yields. A mechanism involvlng addition of an aryl radical to a silyl enol ether is proposed for the latter process.