Liu Y, Zhang Y, Duan HX, Wanyan DY, Wang YQ. Enantioselective organocatalytic Michael additions of N,N'-dialkylbarbituric acids to enones.
Org Biomol Chem 2017;
15:8669-8679. [PMID:
28990625 DOI:
10.1039/c7ob02116j]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N,N'-Dialkylbarbituric acids as cyclic malonamide donors were successfully used in the enantioselective Michael addition reaction of enones. Using cinchona alkaloid-based bifunctional squaramide as an organocatalyst, this Michael reaction of N,N'-di-tert-butylbarbituric acid with various enones features a highly enantioselective (91-99% ee) production of the corresponding optically active 5-substituted barbituric acid derivatives. The transformations of the Michael product for the barbituric acid structural unit were realized in two ways, deprotection to remove the N-tert-butyl group and alkylation to produce 5,5-disubstituted barbituric acid derivatives.
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