Copper-Catalyzed Regioselective Iodoformylation of Terminal Alkynes to Access Versatile Electrophiles (E)-β-Iodo-α,β-Unsaturated Aldehydes

Abstract

Herein, we describe a method for synthesizing (E)β-iodo-α,β-unsaturated aldehydes via the iodoformylation of terminal alkynes with TMSCF 3 and NaI. This synthetic method uses inexpensive and easy-to-handle chemical feedstocks and employs a commercially available CuI catalyst. It can transform a broad range of terminal alkynes into bis-electrophile (E)-β-iodoα,β-unsaturated aldehydes with excellent chemoselectivity, regioselectivity, and stereoselectivity. Moreover, it was demonstrated that this protocol has abundant organic reactivity.

Copper-Catalyzed Cyclization of 2-Alkynylanilines to Give 2-Haloalkoxy-3-alkyl(aryl)quinolines

“…Recently, TMSCF 3 was found to be a difluorocarbene reagent by the Hu and Prakash groups. Inspired by their works and to develop new strategies to construct fluorinated and carbonyl compounds, herein we demonstrate the first example of the synthesis of 2-difluoromethoxyquinolines and 2-iodoalkoxyquinolines via copper-catalyzed cyclization of 2-alkynylanilines with (trifluoromethyl)­trimethylsilane (TMSCF 3 ), sodium iodide (NaI), and anhydrous tetrahydrofuran (THF) (Scheme c). The method exhibits impressive functional group tolerance and substrate scope and gives highly functionalized and complex products in medium to good yields.…”