Synthesis of a <i>C</i><sub>2</sub>-Symmetric Chiral Borinic Acid and Its Application in Catalytic Desymmetrization of 2,2-Disubstituted-1,3-Propanediols
Jian Song, Wen‐Hua Zheng
Abstract
Notwithstanding the common use of boronic acids in catalysis, the design and synthesis of efficient chiral boronic acids remains a formidable challenge. Herein we disclose a rational design and a concise synthesis of a series of novel C 2 -symmetric disubstituted boronic acids, or borinic acids. Chiral borinic acids have been found to be excellent agents that can achieve highly enantioselective desymmetrization of 2,2-disubstituted-1,3-propanediols, providing chiral diols with a quaternary stereocenter, which has been regarded in recent years as challenging. A wide range of substrates are tolerated in this reaction, providing a series of chiral diols with high enantioselectivity. The presence of the tetracoordinate borinate in the catalytic cycle has been proven by 11 B NMR studies, and a stereocontrol model has been proposed.