Synthesis and application of N-methoxy-N-methyl-2-phenylsulfonylacetamide as a two-carbon homologating agent

With the well-known precedence that N-methoxy-N-methyl amides are excellent acyl cation and aldehyde equivalents, N-methoxy-N-methyl-2-phenylsulfonylacetamide (3), a new reagent, synthetically equivalent to (CH2CHO)-C-Theta and (CH2COR)-C-Theta was synthesised. The simplicity involved in the alkylation at the active methylene site in 3, followed by safe removal of the phenylsulfonyl group, makes 3 a versatile reagent for two-carbon homologation of alkyl halides. The method, when applied to sugar halides 6j and 6k led to the synthesis of 2,3-dideoxy sugars.