The oxidative decarboxylation of betulonic, 3,20-dioxo-29-nor-lupan-28-oic, dihydrobetulonic acids with Pb(OAc) 4 in the presence of Py, Cu(OAc) 2 , CF 3 COOH or with PhI(OAc) 2-I 2 leads to 28-nor-lup-16(17)-enes and 28-nor-lup-17(22)-enes, and 17α-acetoxy derivatives. The proportion of regioisomeric olefines is related to a substituent at C-19; the yields of olefines and of acetoxy derivatives depends on reaction conditions and structures of the starting acids. The structures of products were determined by spectroscopic methods.