A Switchable Protocol for Selective Synthesis of gem-Dibromo Compounds and Amides from Ketoximes using TsNBr2

A base controlled metal-free method for selective synthesis of N-substituted amide and alpha,alpha-dibromoketones have been developed by treating ketoximes with N,N-dibromo-p-toluenesulfonamide (TsNBr2) within a very short reaction time. Interesting feature of the process is that the product selectivity can be switched just by addition or exclusion of the base under the identical reaction condition. It was found that addition of a base in the reaction mixture drives the reaction towards a pathway which is completely different from that without having the additive in the medium. Additionally, another novel strategy has also been developed for synthesis of 1-(dibromomethyl)benzenes directly from aldehyde using TsNHNH2 and TsNBr2 under metal-free condition.

Automated summary

A metal-free method has been developed for the selective synthesis of N-substituted amide and alpha,alpha-dibromoketones. The product selectivity can be switched by adding or excluding a base. Additionally, a novel strategy has been developed for the synthesis of 1-(dibromomethyl)benzenes directly from aldehydes under metal-free conditions.