Acetate/Alkoxide/Halide Shuttle Systems Mediated by Lewis Acid Catalysts for Insertion Reaction of a One-Carbon Unit into Carbon-Carbon or Carbon-Halogen Bonds

In this account, we describe our research on a Lewis acid-catalyzed insertion reaction of a-diazo esters into a carbon-carbon or carbon-halogen bond. Indium catalysts mediated not only the insertion of a-diazo esters into a carbon-carbon bond of alkyl acetates, alkyl ethers, acetals, and alkyl halides, but also a carbon-halogen bond of alkyl chlorides, bromides, and iodides. BF3 specifically accelerated the insertion of a-diazo esters into a carbon-fluorine bond. The key to this catalysis is acetate, alkoxide, and halide shuttle systems mediated by a Lewis acid, in which the Lewis acid abstracts a leaving group from a starting substrate and releases the leaving group to the appropriate car-bocation intermediate in the catalytic cycle.