Benzoxaborole Catalyst for Site‐Selective Modification of Polyols
Shuhei Kusano, Shoto Miyamoto, Aki Matsuoka, Yuji Yamada, Ryuta Ishikawa, Osamu Hayashida
Abstract
The site‐selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site‐selective and protecting‐group‐free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a – k were synthesized. In‐depth analysis for the substituent effect revealed that 1i – k , bearing multiple electron‐withdrawing fluoro‐ and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i ‐catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis‐1,2‐diol derivatives proceeded with good yield and site‐selective manner.