Liu C, Zhang L, Li L, Lei M. Theoretical Design of a Catalyst with Both High Activity and Selectivity in C-H Borylation.
J Org Chem 2021;
86:16858-16866. [PMID:
34726921 DOI:
10.1021/acs.joc.1c02070]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Improving both the activity and selectivity of the C-H borylation reaction is currently a hot research topic but also a challenge. In this regard, we suggest a multistrategy combining directing group, coordination unsaturated metal center, and cationic character. Based on Reek's catalyst, we designed a new unsaturated cationic catalyst (1) featuring a directing group for C-H borylation. The calculated free energy barrier of C-H activation is only 7.2 kcal/mol, indicating that the cationic catalyst has higher activity than the original neutral catalyst in this process. Moreover, the comparison suggests that the ortho-C-H borylation pathway is more favorable than the meta and para pathways. The catalyst deconstructions are further performed and prove that the ortho-selectivity is attributed to hydrogen-bonding interactions between the directing group and the substrate, although the ortho site is sterically and electronically unfavorable.
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