Thermal rearrangement of substituted difluoro(methylene)cyclopropane

Both experimental and computational approaches have been employed in the present work to investigate the thermal conversion of substituted difluoro(methylene)cyclopropanes (F2MCP) E-1,1-difluoro-2,2-dimethyl-3-tosylmethylene cyclopropane 1, to the thermodynamically more stable F2MCP products, 1,1-difluoro-2-tosyl-3-(propan-2-ylidene)cyclopropane 2, and 1-(3-(difluoromethylene)-2,2-dimethylcyclopropylsulfonyl)-4-methylbenzene 3. The X-ray crystal structure has been obtained for both 1 and 2, respectively, based on which theoretical analyses on their structure and stability have been carried out. Possible reaction mechanisms are proposed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Thermal rearrangement of difluoro(methylene)cyclopropane was found. ▶ Theoretical calculations revealed that the rearrangement favors a polar pathway. ▶ Difluorocarbene addition to double bond is a kinetically controlled process.