Nishimura K, Ogura Y, Takeda K, Guo W, Ishihara K. Chiral π-Cu(II) Catalysts for the Enantioselective α-Amination of
N-Acyl-3,5-dimethylpyrazoles.
Org Lett 2022;
24:7685-7689. [PMID:
36215133 DOI:
10.1021/acs.orglett.2c03249]
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Abstract
We report the highly enantioselective α-amination of N-acyl-3,5-dimethylpyrazoles with dialkyl azodicarboxylates, catalyzed by in situ generated π-Cu(II) complexes that consist of Cu(OTf)2 and N-(5H-dibenzo[a,d][7]annulen-5-yl)-l-alanine-derived amides, to give the corresponding products as d-α-amino acid derivatives (up to >99% yield and 99% ee). The site-selectivity and enantioselectivity can be satisfactorily explained by the coordination of dialkyl azodicarboxylate with π-Cu(II) complex. The synthetic potential of this one-pot transformation to the α-amino ester is also described.
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