Quezada Víctor, Castroagudín Mariña, Verdugo Felipe, Ortiz Sergio, Zaragoza Guillermo, Nachtigall Fabiane M, Reis Francisco A A, Castro-Alvarez Alejandro, Santos Leonardo S, Nelson Ronald
Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, Avda. Angamos 0610, Antofagasta 1270709, Chile.
Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Concepción 4070371, Chile.
Molecules. 2024 Apr 3;29(7):1604. doi: 10.3390/molecules29071604.
This article describes the development of a nickel-catalyzed regio- and diastereoselective formal [3+2] cycloaddition between -substituted indoles and donor-acceptor cyclopropanes to synthesize cyclopenta[]indoles. Optimized reaction conditions provide the desired nitrogen-containing cycloadducts in up to 93% yield and 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[]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.
本文描述了一种镍催化的区域和非对映选择性形式的[3+2]环加成反应，该反应发生在α-取代吲哚与供体-受体环丙烷之间，用于合成环戊[a]吲哚。优化的反应条件可提供所需的含氮环加成产物，产率高达93%，非对映选择性为8.6:1，且具有完全的区域选择性。底物范围显示出对各种取代吲哚和环丙烷具有高耐受性，从而合成了六种新的环戊[a]吲哚，并分离出文献中先前报道的五种衍生物。此外，通过电喷雾电离质谱（ESI-MS）在线反应监测研究了该反应的机理，从而确定了镍（II）催化过程中的反应中间体。X射线晶体学证实了产物的结构和相对内型立体化学。该方法能够从容易获得的起始原料快速有效地构建稠合二氢吲哚。
