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 CF2H-containing spirocyclopropyloxindoles was developed. Starting from isatin-derived 3-ylideneoxindoles and in situ generated CF2HCHN2, 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 CF2H-substituted analog of HIV-1 NNRTI inhibitor.

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