Cannabicyclol (CBL)

Cannabicyclol (CBL) is a non-psychotomimetic cannabinoid found in the Cannabis species. CBL is a degradative product like cannabinol. Light converts cannabichromene to CBL. Cannabinoids are a class of diverse chemical compounds that act on cannabinoid receptors on cells that repress neurotransmitter release in the brain.

Total syntheses of a series of chromane natural products that contain a cyclobutane ring are described. A unified theme in the strategy employed for all these syntheses is an oxa-[3 + 3] annulation for constructing the chromane nucleus and a stepwise cationic [2 + 2] cycloaddition for the cyclobutane formation. More importantly, the two reactions could be rendered in tandem, thereby providing an expeditious approach to this family of natural products.