Synthetic Strategies for Rare Cannabinoids Derived from .

Efficient syntheses of eight key cannabinoids were established and optimized. Predominant cannabinoids such as cannabigerol (CBG-C) and cannabidiol (CBD-C) were prepared from olivetol via regioselective condensation. Further treatments of CBD led to Δ-tetrahydrocannabinol (THC-C), Δ--tetrahydrocannabinol (-THC-C), and cannabinol (CBN-C). Alternatively, a [3 + 3] annulation between olivetol and citral yielded the minor cannabinoid cannabichromene (CBC-C), which was converted into two very rare polycycles, cannabicyclol (CBL-C) and cannabicitran (CBT-C), in a one-pot reaction. Finally, all eight syntheses were extended by utilizing resorcinol and two phenolic analogues, achieving a cannabinoid group with more than 30 compounds through a facile synthesis strategy.