Lewis Base‐Boryl Radicals Promoted Selective Mono‐ and Di‐ Hydrodechlorination of Trichloroacetamides and Acetates

Mono and dichloro‐substituted organic molecules are shown to possess significant roles in various fields, especially in medicinal chemistry. One approach to synthesizing these compounds involves the selective dechlorination of easily prepared trichloromethyl compounds. Nevertheless, developing a practical approach that allows selective mono‐ and dihydrodechlorination is a challenging task. Herein, we introduced a method for selective mono‐ and dihydrodechlorination of trichloroacetamides and acetates which was promoted by two different Lewis base‐boryl radicals. Accordingly, 4‐dimethylaminopyridine (DMAP)‐borane enabled mono‐substitution of chlorine atom by hydrogen while dihydro‐substitution of chlorine atoms was promoted by N‐heterocyclic carbene (NHC)‐boryl radical. Using deuterated Lewis base‐borane as deuterium atom source, mono‐ and dideuterodechlorination were also successfully took place. This protocol features broad substrate scope and operates under mild reaction conditions.