Copper-Catalyzed Borylation of Cyclic Sulfamidates: Access to Enantiomerically Pure (β-and γ-Amino­alkyl)boronic Esters

Abstract

Cyclic sulfamidates undergo borylation under copper-catalyzed conditions using B2pin2to give enantiomerically (and diasteromerically) defined (aminoalkyl)boronic esters. External iodide is essential, but the intermediacy of simple alkyl iodides has been excluded; N-sulfated intermediates are key in the borylation sequence. Based on stereochemical studies and trapping experiments, the involvement of carbon-centered radicals under these copper-catalyzed conditions appears likely.