Construct indeno[1,2-b]oxepine orcis-cyclopropylacrylate by sulfur ylides

For the first time, the [4 + 3] or [2 + 1] annulation of crotonate-derived sulfur ylides with arylidenemalononitrile or arylidene-1H-indene-1,3(2H)-dione is reported using Na₂CO₃as the base.