6-Deoxythebaine (3) has been prepared as a precursor to C-6 alkyl substituted orvinols 15 and 17. The C-6 methyl group was introduced by addition of methyllithium to codeinone. Transformation of 6-methylcodeine to its 6-methyl ether and 1,4-elimination of methanol with potassium tert-butoxide in Me2SO then gave 6-deoxythebaine (3) in 49% overall yield. Diels-Alder addition of methyl vinyl ketone to this diene yielded four ketones: three regio- and stereoisomeric 6,14-endo-ethenomorphinans and one exo adduct. The major ketone isomer provided the set of C-19 diastereomeric orvinols 15 in which the pendant carbon has the 7 alpha configuration. Regioisomeric ketone 8, in which the acetyl group is at C-8, was formed in 3% yield and was similarly converted to the corresponding orvinols 17. Orvinol (R)-15 (R at C-19) is an analgesic of very high potency, 2200 times that of morphine; regioisomeric orvinols 17, in which the pendant tertiary alcohols are on C-8, are much less potent. The higher activity of the C-6 methyl and methoxyl analogues (R)-15 and (R)-22 relative to hydrogen-substituted (R)-19 indicates that C-6 alkyl substitution enhances analgesic potency.