CO2 Activation by Lewis Pairs Generated Under Copper Catalysis Enables Difunctionalization of Imines

• Published in: Journal of the American Chemical Society Vol. 142; no. 4; pp. 1966 - 1974
• Main Authors: Li, Zhenghua, Zhang, Liang, Nishiura, Masayoshi, Luo, Gen, Luo, Yi, Hou, Zhaomin
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 29.01.2020; Amer Chemical Soc
• Subjects: aldimines; carbon dioxide; carbon dioxide fixation; catalytic activity; chemical bonding; Chemistry; Chemistry, Multidisciplinary; copper; diastereoselectivity; feedstocks; lithium; Physical Sciences; Science & Technology; value added; TRANSFORMATION; ALKENES; ALDIMINES; ASYMMETRIC-SYNTHESIS; ACID-CHLORIDES; REDUCTION; ESTERS; CARBOXYLATION; MULTICOMPONENT SYNTHESIS; CARBON-DIOXIDE
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.9b11423

Integration of distinct substrate activation modes in a catalytic circle is critical for the development of new, powerful synthetic methodologies toward complex and value-added chemicals from simple and readily available feedstocks. Here, we describe a highly selective difunctionalization of imines through incorporation of activation of CO2 by intramolecular N/B Lewis pairs into a copper catalytic cycle. Experimental and computational studies on the mechanistic aspect revealed an α-borylalkylamido intermediate, a metal amide-based Lewis pair formed by borylation of a C–N double bond, and enabled an unprecedented CO2 fixation pattern that is in sharp contrast to the traditional CO2 insertion into transition-metal-element bonds. The unique lithium cyclic boracarbamate products could be easily transformed into multifunctional N-carboxylated α-amino boronates. The highly diastereoselective reactions of chiral N-tert-butanesulfinyl aldimines were also achieved. We hope that our findings may inspire further development of selective multicomponent reactions by incorporation of Lewis pair chemistry into transition-metal catalysis.