Isomer-sensitive deboronation in reductive aminations of aryl boronic acids

Abstract

Boronic acids (BAs) are useful functionalities for programmable stimuli-responsive chemistry, due to their Lewis acid character with pK a values tunable across physiological pH and their reversible binding to saccharides, catechols, and other compounds bearing 1,2-diol moieties. 1 In addition, BAs have emerged as valuable reagents and intermediates in important synthetic pathways, such as Suzuki cross-coupling reactions, 1 and as selective enzyme inhibitors, exemplified by the commercial success of the anti-cancer drug Bortezomib. 2 Over the last decade, researchers have studied a variety of BA-modified peptides, focusing on the inhibitory properties of the BA or the use of the BA as a functional element in peptide self-assembly. 3 For example, our group has recently reported the reversible selfassembly behavior of a BA dipeptide, controllable by pH, ionic strength, and the addition of polyols. 3s