Syntheses of CF2H-containing spirocyclopropyloxindoles from in situ generated CF2HCHN2 and 3-ylideneoxindoles

A facile and practical [3+2] cycloaddition/ring contraction for the construction of structurally diverse CF 2 H-containing spirocyclopropyloxindoles was developed. Starting from isatin-derived 3-ylideneoxindoles and in situ generated CF 2 HCHN 2 , the desired products were obtained in good to excellent results (up to 99% yield and >99:1 trans/cis ) in the absence of metal catalyst . The potential application of the protocol was also demonstrated by the synthesis of the CF 2 H-substituted analog of HIV-1 NNRTI inhibitor.