Reduction of benzoyl tributylphosphonium chlorides by samarium diiodide asa novel access to 4-benzoylbenzaldehydes

Addition of samarium diiodide to a well-stirred THF solution of benzoyl tri butylphosphonium chlorides generated in situ from benzoyl chlorides and tri butylphosphine at -40 degreesC gave 4-benzoylbenzaldehydes as predominant p roducts from benzoyl chlorides without para-substituents, while benzoyl chl oride bearing p-methyl or chloro groups was exclusively converted into the corresponding alpha -diketone.