Arylboration of Enecarbamates for the Synthesis of Borylated Saturated N-Heterocycles

Abstract

Two catalytic systems have been developed for the arylboration of endocyclic enecarbamates to deliver synthetically versatile borylated saturated N-heterocycles in good regio- and diastereoselectivities. A Cu/Pd dual catalytic reaction enables the synthesis of borylated, α-arylated azetidines, while a Ni-catalysed arylboration reaction efficiently functionalizes 5-, 6-, and 7-membered enecarbamates. In the case of the Cu/Pd-system, a remarkable additive effect was identified that allowed for broader scope. The products are synthetically useful, as demonstrated by manipulations of the boronic ester to access biologically active compounds.