Liu Y, Ye L, Shi Z, Yang X, Zhao Z, Li X. Highly enantioselective Michael addition of α-nitroacetate to α,β-unsaturated pyrazolamide catalyzed by a bifunctional squaramide.
Chirality 2018;
30:1287-1303. [PMID:
30286255 DOI:
10.1002/chir.23023]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/20/2018] [Accepted: 08/30/2018] [Indexed: 01/03/2023]
Abstract
A highly enantioselective (91- > 99% ee) Michael addition of α-nitroacetate to α,β-unsaturated pyrazolamide was developed in the presence of a bifunctional squaramide. Satisfactory isolated yields (42%-99%) have been achieved with a wide range of α,β-unsaturated pyrazolamides, albeit acceptor of this type displayed poor reactivity in the precedent reports. The adducts resulting from this protocol are useful synthetic intermediates for further synthetic modification.
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