Cycloaddition of trifluoromethyl azafulvenium methides: synthesis of new triflu...

• Author(s): Nunes, Cláudio M. ; Silva, Manuela Ramos ; Beja, Ana Matos ; Fausto, Rui ; Melo, Teresa M.V.D. Pinho e
• Date: 2010
• Persistent ID: http://hdl.handle.net/10316/18065
• Origin: Estudo Geral - Universidade de Coimbra
• Document Type: Article
• Language: English

Description

The chemistry of trifluoromethyl azafulvenium methides was explored leading to a new route to trifluoromethylpyrrole-annulated systems. The first evidence of azafulvenium methides acting as 1,3-dipoles is reported. These azafulvenium methides showed site selectivity in the reaction with strong electron-deficient dipolarophiles leading exclusively to 1,3-cycloadducts. In the cycloaddition with less-activated dipolarophiles 1,7-cycloadducts resulting from [8π+2π] cycloaddition are also formed. FMO analysis of the cycloaddition reactions allowed the rationalization of the observed selectivity. Graphical abstract