On the features of reactivity of 8-[(1E)-2-phenylethenyl]-substituted thebaine and codeinone derivatives

An improved method for the synthesis of 8-[(1 E )-2-phenylethenyl]codeinone dimethyl ketal was described. The ability of [(1 E )-2-phenylethenyl] substituent to stabilize effectively the π-system of the ring C is responsible for the essential difference in both the reactivity and the compositions of products formed in the reactions of the corresponding substituted and unsubstituted codeinone and thebaine derivatives.