A concise formal synthesis of (-)-hamigeran B.

A concise and efficient formal synthesis of (-)-hamigeran B is reported. The critical intermediate was synthesized from 3-methoxy-5-methylphenyl trifluoromethanesulfonate with an 11-steps 7.2% total yield route. The chiral quaternary carbon was efficiently and steroselectively constructed through an intermolecular Pauson-Khand reaction and a Claisen rearrangement reaction with >99% ee; the cyclohexane B was then closed through an aldehyde Friedel-Crafts cyclization. Lastly, the isopropenyl group of ring C was introduced through a Suzuki coupling reaction.