Catalytic Enantioselective Cyclopropenation of Internal Alkynes: Access to Difluoromethylated Three-Membered Carbocycles

Zhi-Qi Zhang; Meng-Meng Zheng; Xiao-Song Xue; Ilan Marek; Fa-Guang Zhang; Jun-An Ma

doi:10.1002/anie.201911701

Catalytic Enantioselective Cyclopropenation of Internal Alkynes: Access to Difluoromethylated Three-Membered Carbocycles

Angew Chem Int Ed Engl. 2019 Dec 9;58(50):18191-18196. doi: 10.1002/anie.201911701. Epub 2019 Nov 11.

Authors

Zhi-Qi Zhang^{1

2}, Meng-Meng Zheng³, Xiao-Song Xue³, Ilan Marek⁴, Fa-Guang Zhang^{1

2}, Jun-An Ma^{1

2

3}

Affiliations

¹ Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Tianjin Collaborative Innovation Centre of Chemical Science & Engineering, Tianjin University, Tianjin, 300072, P. R. China.
² Joint School of NUS & TJU, International Campus of Tianjin University, Fuzhou, 350207, P. R. China.
³ State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, P. R. China.
⁴ Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200009, Israel.

PMID: 31633856
DOI: 10.1002/anie.201911701

Abstract

Herein we described an efficient Rh^II -catalyzed enantioselective cyclopropenation reaction of internal alkynes with a masked difluorodiazoethane reagent (PhSO₂ CF₂ CHN₂ , Ps-DFA). This asymmetric transformation offers efficient access to a broad range of enantioenriched difluoromethylated cyclopropenes (40 examples, up to 99 % yield, 97 % ee). The synthetic utility of obtained strained carbocycles is demonstrated by subsequent stereodefined processes, including cross-couplings, hydrogenation, Diels-Alder reaction, and Pauson-Khand reaction.

Keywords: cyclopropenation; diazo compounds; homogeneous catalysis; internal alkynes; metal carbenes.

Abstract

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