New Dicarboxylic Acid Anhydride for Ambient-Temperature Castagnoli-Cushman Reactions

摘要

A novel 3-phenyl-4-thiaglutaric anhydride was employed as a highly reactive partner for the Castagnoli-Cushman reaction. This, in combination with the use of DMF as a reaction me- dium, resulted in a drastic lowering of the reaction temperature to ambient (compared to the 110–150 ℃ range typical for sim- ilar processes involving glutaric anhydride) and an extended re- action scope (with respect to substitution pattern in the imine component). Diastereomeric products were separated, in the form of respective methyl esters, and their comparative NMR characterization led to preliminary generalizations regarding the syn- and anti-series.