Cannabinoid research depends on synthesizing derivatives for structure-activity relationship studies. (-)-Δ9-Tetrahydrocannabinol and cannabidiol were synthesized via a tandem enantioselective conjugate addition/enolate alkylation annulation with a novel ambiphilic trifluoroborate in seven steps. A new class of alkenyl and aryl ambiphilic trifluoroborates were synthesized and showed great compatibility with various functional groups, high yields, and excellent enantio- and diastereoselectivity. A novel benzo-fused cannabinoid analogue and tandem quaternary stereocenter-containing reaction products were synthesized with good to excellent enantioselectivity.