A stereoselective synthesis of naturally occurring (+)-20R-dihydrocleavamine by photo-[2+2]-cycloreversion

A stereoselective synthesis of (+)-20R-dihydrocleavamine, an alkaloid from Pandaca eusepala and Tabernamontana eglandulose, has been developed using an enantiopure tricyclic ketone accessible from a meso precursor by employing a photo-[2+2]-cycloreversion reaction as the key step.