Cho B, Wong MW. Unconventional Bifunctional Lewis-Brønsted Acid Activation Mode in Bicyclic Guanidine-Catalyzed Conjugate Addition Reactions.
Molecules 2015;
20:15108-21. [PMID:
26295222 PMCID:
PMC6331857 DOI:
10.3390/molecules200815108]
[Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 06/03/2015] [Accepted: 08/10/2015] [Indexed: 01/26/2023] Open
Abstract
DFT calculations have demonstrated that the unconventional bifunctional Brønsted-Lewis acid activation mode is generally applicable to a range of nucleophilic conjugate additions catalyzed by bicyclic guanidine catalysts. It competes readily with the conventional bifunctional Brønsted acid mode of activation. The optimal pro-nucleophiles for this unconventional bifunctional activation are acidic substrates with low pKa, while the best electrophiles are flexible 1,4-diamide and 1,4-diester conjugated systems.
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