Reaktionen von dienen mit dem dichlorcarbenreagens von makosza und wawrzyniewicz

Compared to dichlorocarbene from other sources the highly reactive dichloro carbene reagent of Makosza and Wawrzyniewicz gives better yields of bis- und tris-adducts even with compounds lacking activation. Compounds 4, 10, and 11 have been prepared for the first time; Compounds 10 and 11 show unusual long-range couplings between methyl protons 5 bonds apart.