Title: Copper(I)‐Catalyzed Enantioconvergent Borylation of Racemic Benzyl Chlorides Enabled by Quadrant‐by‐Quadrant Structure Modification of Chiral Bisphosphine Ligands.
Authors: Iwamoto, Hiroaki; Endo, Kohei; Ozawa, Yu; Watanabe, Yuta; Kubota, Koji; Imamoto, Tsuneo; Ito, Hajime
Abstract: The first copper(I)‐catalyzed enantioselective borylation of racemic benzyl chlorides has been realized by a quadrant‐by‐quadrant structure modulation of QuinoxP*‐type bisphosphine ligands. This reaction converts racemic mixtures of secondary benzyl chlorides into the corresponding chiral benzylboronates with high enantioselectivity (up to 92 % ee). The results of mechanistic studies suggest the formation of a benzylic radical intermediate. The results of DFT calculations indicate that the optimal bisphosphine‐copper(I) catalyst engages in noncovalent interactions that efficiently recognize the radical intermediate, and leads to high levels of enantioselectivity.
Subjects: BENZYL chloride; BORYLATION; BENZYLIC group; LIGANDS (Chemistry); COPPER; KINETIC resolution; RACEMIC mixtures
Publication: Angewandte Chemie, 2019, Vol 131, Issue 32, p11229
ISSN: 0044-8249
Publication type: Academic Journal
DOI: 10.1002/ange.201906011

Copper(I)‐Catalyzed Enantioconvergent Borylation of Racemic Benzyl Chlorides Enabled by Quadrant‐by‐Quadrant Structure Modification of Chiral Bisphosphine Ligands.

Iwamoto, Hiroaki; Endo, Kohei; Ozawa, Yu; Watanabe, Yuta; Kubota, Koji; Imamoto, Tsuneo; Ito, Hajime