A catalyst-free bis(triflyl)ethylation/benzannulation reaction: rapid access to carbazole-based superacidic carbon acids from alkynols

Irene Martín-Mejías; Cristina Aragoncillo; Hikaru Yanai; Shoki Hoshikawa; Yuuki Fujimoto; Takashi Matsumoto; Pedro Almendros

doi:10.1039/c9cc08930f

A catalyst-free bis(triflyl)ethylation/benzannulation reaction: rapid access to carbazole-based superacidic carbon acids from alkynols

Chem Commun (Camb). 2020 Feb 11;56(12):1795-1798. doi: 10.1039/c9cc08930f. Epub 2020 Jan 17.

Authors

Irene Martín-Mejías¹, Cristina Aragoncillo², Hikaru Yanai³, Shoki Hoshikawa³, Yuuki Fujimoto³, Takashi Matsumoto³, Pedro Almendros¹

Affiliations

¹ Instituto de Química Orgánica General, IQOG-CSIC, Juan de la Cierva 3, 28006-Madrid, Spain. palmendros@iqog.csic.es.
² Grupo de Lactamas y Heterociclos Bioactivos, Departamento de Química Orgánica, Unidad Asociada al CSIC, Facultad de Química, Universidad Complutense de Madrid, 28040-Madrid, Spain.
³ School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan. yanai@toyaku.ac.jp.

PMID: 31950123
DOI: 10.1039/c9cc08930f

Abstract

Carbazoles possessing Tf₂CHCH₂ groups were obtained by the reaction of 1-(indol-2-yl)but-3-yn-1-ols with in situ-generated Tf₂C[double bond, length as m-dash]CH₂ through vicinal difunctionalisation of the alkyne moiety, where the vinyl-type carbocation intermediate was selectively attacked by the indole moiety and not by the carbanion moiety.