Thebaine Cyclopropanation.

[1+2]Cycloaddition to thebaine alcaloid under catalysis by copper triflate of carbene generated from CH2N2 occurred stereoselectively affording 6β,7β-methylene-6,7-dihydrothebaine. The simultaneously proceeding 8β,14β-cyclopropanation and nitrogen quaternization furnished N,N-dimethyl-N-nor-8β,14β-methylene-8,14-dihydrothebaine triflate whose structure was established by X-ray diffraction analysis. The possibility of preparation of 14β-hydroxy-6β,7β-methylene-8α-substituted dihydrocodeine derivatives was demonstrated. [ABSTRACT FROM AUTHOR]