Campbell CD, Greenaway RL, Holton OT, Walker PR, Chapman HA, Russell CA, Carr G, Thomson AL, Anderson EA. Ynamide carbopalladation: a flexible route to mono-, bi- and tricyclic azacycles.
Chemistry 2015;
21:12627-39. [PMID:
26189754 PMCID:
PMC4557052 DOI:
10.1002/chem.201501710]
[Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 11/09/2022]
Abstract
Bromoenynamides represent precursors to a diversity of azacycles by a cascade sequence of carbopalladation followed by cross-coupling/electrocyclization, or reduction processes. Full details of our investigations into intramolecular ynamide carbopalladation are disclosed, which include the first examples of carbopalladation/cross-coupling reactions using potassium organotrifluoroborate salts; and an understanding of factors influencing the success of these processes, including ring size, and the nature of the coupling partner. Additional mechanistic observations are reported, such as the isolation of triene intermediates for electrocyclization. A variety of hetero-Diels-Alder reactions using the product heterocycles are also described, which provide insight into Diels-Alder regioselectivity.
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