Affiliation:
1. Département de Chimie Université Laval 1045 Avenue de la Médecine Québec Québec G1 V 0 A6 Canada
2. Department of Chemistry and Biotechnology Graduate School of Engineering The University of Tokyo Bunkyo-Ku Tokyo 113-8656 Japan
Abstract
AbstractThe borylation of Csp3−H bonds is a challenging transformation that is typically restricted to transition metal catalysis. Herein, we report the site‐selective metal‐free Csp3−H borylation of saturated cyclic amines. It is possible to selectively borylate piperidine derivatives at the α or β positions according to the reaction conditions. The mechanism was supported by NMR spectroscopy, calorimetry experiments and density functional theory (DFT) computations. It suggests that the piperidine is dehydrogenated by complexation with BBr3 to produce an enamine intermediate, which is in turn borylated at either the α or β position according to the reaction conditions.
Funder
Natural Sciences and Engineering Research Council of Canada