Tetrahydrocannabinol revisited: Synthetic approaches utilizing molybdenum catalysts

Article abstract of DOI:10.1135/cccc20011257

Δ⁹-Tetrahydrocannabinol 1 and its isomers were synthesized via domino-type methodology. The first approach, leading to (±)-1, relies on the Mo(IV)-catalyzed, one-pot cascade reaction of citral (4) with olivetol (15), affording (±)-Δ⁹-tetrahydrocannabinol as a 69 : 31 mixture of the trans-(natural) and cis-isomers in 20% yield. The alternative approach, leading to natural (-)-1, commenced with epoxidation of (+)-limonene (R)-(+)-16; opening of the resulting cis-epoxide 17 with PhSeNa, followed by elimination, afforded tertiary alcohol 21, whose acetate 22 was treated with olivetol 15 in the presence of Mo(II) catalyst IV to afford (-)-1 in 52% yield.