摘要 : Results from the thermal reactions of deuterated dienes 12-15 provide evidence of the concertedness of the [4 + 1]-cycloaddition between dimethoxycarbene and electron-deficient dienes. Other evidence suggests that the main pathway... 展开 Results from the thermal reactions of deuterated dienes 12-15 provide evidence of the concertedness of the [4 + 1]-cycloaddition between dimethoxycarbene and electron-deficient dienes. Other evidence suggests that the main pathway is a concerted [4 + 1]-cycloaddition rather than a cyclopropanation followed by a vinylcyclopropane rearrangement. Ionic pathways can become competitive when steric or geometrical constraints are present. 收起