Pan Z, Pound SM, Rondla NR, Douglas CJ. Intramolecular aminocyanation of alkenes by N-CN bond cleavage.
Angew Chem Int Ed Engl 2014;
53:5170-4. [PMID:
24719371 PMCID:
PMC4077192 DOI:
10.1002/anie.201310983]
[Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/06/2014] [Indexed: 11/06/2022]
Abstract
A metal-free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C6F5)3 activates N-sulfonyl cyanamides, thus leading to a formal cleavage of the N-CN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom-economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups. Labeling experiments with (13)C suggest a fully intramolecular cyclization pattern due to the lack of label scrambling in double crossover experiments. Catalysis with Lewis acid is realized and the reaction can be conducted under air.
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