Synthesis of a CF3-substituted 1,3,4-oxadiazoline and its use in the generation and trapping of an ?-trifluoromethyl carbene

Among the different methods allowing the introduction of a CF 3 group into an organic framework, those based on the use of a fluorinated carbene intermediate are particularly useful. They can lead to the formation of structural motifs that are difficult to access by other means. We report in this article the development of a new route allowing the generation of an  -trifluoromethyl  -benzyloxy carbene from a readily accessible trifluoromethyl 1,3,4-oxadiazoline. Trapping of the carbene in the presence of various alkynes led to the formation of various protected trifluoromethyl tertiary cyclopropenols in moderate yields.