Process for production of delta-9- tetrahydrocannabinol

Disclosed is a process for the preparation of a delta-9-tetrahydrocannabinol product as represented by the general formula (I), wherein: R1 is H, alkyl, carboxylic ester, or acyl; R2 is H, OH, protected hydroxyl, alkyl, alkenyl, alkynyl, acyl, aryl, or heteroaryl; R3 is H, alkyl, carboxylic ester, or acyl; and R4 is H, alkyl, silyl, acyl, alkylsulfonyl, arylsulfonyl, alkylphosphoryl, or arylphosphoryl; said process comprising: treating a first intermediate compound of the formula (II) such as cannabidiol with an organoaluminium-based Lewis acid catalyst (such as triisobutylaluminium, ethyl aluminium dichloride, diethylaluminium chloride, isobutyl aluminium dichloride, diisobutylaluminium chloride, trimethylaluminium, triethylaluminium, triisopropylaluminium, trioctylaluminium, tridecylaluminium, diisobutylaluminium acetate), in an organic solvent (such as hexane, heptane, toluene, xylene, dichloromethane, or mixtures thereof) under conditions effective to produce the product compound.