Preparation of methylenedifluorocyclopropanes via cyclopropyl anion promoted β-elimination

Article abstract of DOI:10.1016/S0040-4020(99)00588-8

Preparation of methylenedifluorocyclopropanes 2 through the β- elimination reaction promoted by difluorocyclopropyl anion formed by cleavage of C-Si bond with TBAF is described. Base-catalyzed isomerization of 2 to difluorocyclopropene 11 shows the latter structure thermodynamically more stable in contrast to non-fluorinated cases. Application of this method to the synthesis of methylenedifluorocyclopropylglycine (F₂MCPG) derivative 17 is also presented.