Nickel(II)-Catalyzed Formal [3+2] Cycloadditions between Indoles and Donor–Acceptor Cyclopropanes

Autor: Víctor Quezada, Mariña Castroagudín, Felipe Verdugo, Sergio Ortiz, Guillermo Zaragoza, Fabiane M. Nachtigall, Francisco A. A. Reis, Alejandro Castro-Alvarez, Leonardo S. Santos, Ronald Nelson
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Molecules, Vol 29, Iss 7, p 1604 (2024)
Druh dokumentu: article
ISSN: 1420-3049
DOI: 10.3390/molecules29071604
Popis: This article describes the development of a nickel-catalyzed regio- and diastereoselective formal [3+2] cycloaddition between N-substituted indoles and donor–acceptor cyclopropanes to synthesize cyclopenta[b]indoles. Optimized reaction conditions provide the desired nitrogen-containing cycloadducts in up to 93% yield and dr 8.6:1 with complete regioselectivity. The substrate scope showed high tolerance to various substituted indoles and cyclopropanes, resulting in the synthesis of six new cyclopenta[b]indoles and the isolation of five derivatives previously reported in the literature. In addition, a mechanistic proposal for the reaction was studied through online reaction monitoring by ESI-MS, allowing for the identification of the reactive intermediates in the Ni(II) catalyzed process. X-ray crystallography confirmed the structure and relative endo stereochemistry of the products. This method enables the fast and efficient construction of fused indolines from readily accessible starting materials.
Databáze: Directory of Open Access Journals
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