Gonzalez KJ, Rand AW, Stoltz BM. Development of a Non-Directed Petasis-Type Reaction by an Aromaticity-Disrupting Strategy.
Angew Chem Int Ed Engl 2023;
62:e202218921. [PMID:
36763681 PMCID:
PMC10033435 DOI:
10.1002/anie.202218921]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/12/2023]
Abstract
The Petasis-type reaction, which couples an imine and boronic acid, is an important tool for C-C bond formation in organic synthesis. However, the generality of this transformation has been limited by the requirement for a directing heteroatom to enable reactivity. Herein, we report the development of a non-directed Petasis-type reaction that allows for the coupling of trifluoroborate salts with α-hydroxyindoles. By disrupting aromaticity to generate a reactive iminium ion, in conjunction with using trifluoroborate nucleophiles, the method generates a new C-C bond without the need for a directing group. This reaction is operationally simple, providing α-functionalized indoles in up to 99 % yield using sp, sp2 , and sp3 -hybridized trifluoroborate nucleophiles. Finally, this reaction is applied as a novel bioconjugation strategy to link biologically active molecules and toward the convergent synthesis of non-natural heterodimeric bisindole alkaloid analogs.
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