[4+3] Cycloaddition of Donor-Acceptor Cyclopropanes with Amphiphilic Benzodithioloimine as Surrogate for ortho-Bisthioquinone.

Donor-acceptor cyclopropanes were reacted with amphiphilic benzodithioloimine to give seven-membered heterocycles with two sulfur atoms. Formally, this transformation can be regarded as a [4+3] cycloaddition reaction of the three-membered ring and ortho-bisthioquinone. The benzodithioloimine serves as a surrogate for this highly reactive diene. The structure of the products was confirmed by X-ray crystallography. Broad signals in (13) C NMR studies suggest that several conformers, slowly interconverting on the NMR timescale, are present at room temperature.