“…Analogously, the formed 20-methylthevinone (194, Figure 52) was converted to 20,20-dimethyl-thevinone (195, 76%) and the latter to 20,20,20-trimethylthevinone (196, 59%). The latter compound was identical to the tert-butyl vinyl ketone adduct (196) of thebaine [160]. N 17 -Cycopropylmethyl-northevinone (310) was also converted in the same manner to its 20-methyl-(194, R = CPM, 98%), 20,20-dimethyl-(195, R = CPM, 91%), and 20,20,20-trimethyl-analogues (196, R = CPM, 42%), and the method was also successfully extended to numerous 7,8-constrained-and 7,7-spiro-thevinone derivatives.…”