Abstract
α-Acyl-α-benzylsulfonyldiazomethanes (2a-d) have been converted to α-benzylsulfonyl-α-substituted-acetic acids (7a-d) by means of the Wolff rearrangement. Reductive removal of the benzylsulfonyl group of 7b-d can be achieved by the use of sodiumethanol in tetrahydrofuran. α-Benzylsulfonyl-α-substituted-propionic acids (9a-d), prepared from benzyl α-benzylsulfonyl-α-substituted-acetates (3a-d), were also debenzyl-sulfonylated under similar reductive conditions. The overall process, in combination with the Arndt-Eistert synthesis of α-sulfonylacetates from acyl chlorides and benzylsulfonyl-diazomethane (1), provides a new, safe method for the homologation of carboxylic acids.
