Two .DELTA.8-THC [tetrahydrocannabinol] derivatives, 3-(3-oxo-1-octenyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyranolol (4a) and 3-(3-hydroxy-1-octenyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyrano-1-ol (4b), with functionalized side-chains were synthesized. Treatment of (+)-trans-p-mentha-2,8-dien-1-ol with the resorcinal (5-(1,3-dithiolan-2-yl) resorcinol) followed by removal of the dithiol group with HgO-BF3.cntdot.Et2O gave the aldehyde 3-formyl-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-1-ol. A Wittig reaction of dimethyl (2-oxoheptyl)phosphate with the aldehyde furnished 4a, which was reduced to 4b. Compounds 4a and 4b showed potent cannabinoid-like activity in mice.