Wang Y, Zheng C, You SL. Iridium-Catalyzed Asymmetric Allylic Dearomatization by a Desymmetrization Strategy.
Angew Chem Int Ed Engl 2017;
56:15093-15097. [PMID:
28980373 DOI:
10.1002/anie.201708419]
[Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Indexed: 12/13/2022]
Abstract
A desymmetrization strategy was developed involving iridium-catalyzed allylic dearomatization of indoles. The six-membered-ring spiroindolenines contain three contiguous stereogenic centers, including an all-carbon quaternary center, and were obtained in up to 99 % yield with 99 % ee and >95:5 d.r. When treated with a catalytic amount of tosylic acid, six-membered spiroindolenine undergoes an unprecedented six-to-seven-membered ring expansion, affording the corresponding hexahydroazepino[4,5-b]indole.
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