Interaction of thiophene S,N-ylides with dimethyl acetylenedicarboxylate
Abstract
The title reaction yields two products, dimethyl tetrachlorophthalate, by [4 + 2] cycloaddition and dimethyl 2-chloro-3-ethoxycarbonylimino-2-trichloro-2-thienylsuccinate by [6 + 2] cycloaddition. The latter structure, verified by X-ray crystallography, corrects an earlier report.