An Ag-catalyzed formal [3+2]-cycloaddition of α-trifluoromethylated methyl isocyanides with polar double bonds has been developed for the facile access to trifluoromethylated oxazolines, imidazolines and pyrrolines under mild conditions. The practicality of this chemistry is demonstrated by the gram-scale synthesis of oxazolines with excellent yields and facile transformations of the formed oxazolines to trifluoromethylated β-amino alcohols in quantitative yields.

An unprecedented chemoselective double annulation of α-trifluoromethylated isocyanides with o-acylaryl isocyanides has been developed. This new reaction provides a rapid, efficient, and complete atom-economic strategy for the synthesis of trifluoromethylated oxadiazino[3,2-a]indoles in a single operation from readily available starting materials. Isocyanide insertion into C═O double bonds is disclosed for the first time as indicated by the results of O-labeling experiment. A mechanism for this domino reaction is proposed involving chemoselective heterodimerization of two different isocyanides, followed by indole-2,3-epoxide formation and rearrangement.