Ring-Opening 1,3-Halochalcogenation of Cyclopropane Dicarboxylates

Donor–acceptor
cyclopropanes with two geminal carboxylic
esters are reacted with chalcogenyl chlorides and bromides to afford
ring-opened products bearing the halogen atoms in the 1-position,
adjacent to the donor, and the chalcogenyl residue in the 3-position
next to the two acceptor groups. A variety of different donors (e.g.,
aryl, N, and O) are used. The stereospecificity of the reaction is
demonstrated by using a chiral starting material.