Ligand-Controlled Regiodivergent Cyanoboration of Internal Allenes by Copper Catalysis

Hui Hu; Guo-Cui Ji; Linjuan Jiang; Siwei Bi; Yuan-Ye Jiang; Yuanhong Liu

doi:10.1002/anie.202210338

Ligand-Controlled Regiodivergent Cyanoboration of Internal Allenes by Copper Catalysis

Angew Chem Int Ed Engl. 2022 Dec 19;61(51):e202210338. doi: 10.1002/anie.202210338. Epub 2022 Nov 17.

Authors

Hui Hu¹, Guo-Cui Ji², Linjuan Jiang³, Siwei Bi², Yuan-Ye Jiang², Yuanhong Liu¹

Affiliations

¹ State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P. R. China.
² School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165, P. R. China.
³ School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.

PMID: 36266741
DOI: 10.1002/anie.202210338

Abstract

The first copper-catalyzed regiodivergent cyanoboration of internal allenes with B₂ pin₂ (bis(pinacolato)diboron) and NCTS (N-cyano-N-phenyl-p-toluenesulfonamide) derivatives is reported. The β,γ- and α,β-cyanoborylated products were synthesized with high regio- and stereo-selectivity. Computational studies revealed that nucleophilic addition of allylcopper or related intermediates on cyanation reagent is the regio- and stereo-determining step, while transmetalation with B₂ pin₂ is the rate-determining step. The nucleophilic addition step proceeds via inner-sphere mechanism in the Cu^I /P(o-tol)₃ and Cu^I /Xantphos (P(o-tol)₃ =tris(o-methylphenyl)phosphine, Xantphos=4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) catalytic systems and via outer-sphere mechanism in the Cu^II /Xantphos catalytic system, respectively.

Keywords: Copper Catalysis; Cyanoboration; DFT Calculations; Internal Allenes; Regiodivergent.

Abstract

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