Asymmetric Synthesis of Axially Chiral Arylpyrazole via an Organocatalytic Arylation Reaction
Xi Gao1, Chengwen Li1, Li Chen1,2
1State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Abstract:
Herein, a highly enantioselective arylation reaction of 3-aryl-5-aminopyrazoles and quinone derivatives was realized using a chiral phosphoric acid catalyst under mild conditions. The reaction has a broad scope with respect to both arylation reaction partners and hence offers rapid access to an array of axially chiral arylpyrazoles with pretty outcomes (up to 95% yield and 99% ee). Notably, the reaction is very efficient, as the catalyst loadings for the model reaction can be reduced to 1 mol % and the enantioselectivity is still maintained. Besides, the synthetic utility of the protocol was proven by a gram-scale reaction and the transformation of the product.
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