Efficient and modular synthesis of ibogaine and related alkaloids.

Anecdotal reports and preliminary clinical trials suggest that the psychoactive alkaloid ibogaine and its active metabolite noribogaine have powerful anti-addictive properties, producing long-lasting therapeutic effects across a range of substance use disorders and co-occurring neuropsychiatric diseases such as depression and post-traumatic stress disorder. Here we report a gram-scale, seven-step synthesis of ibogaine from pyridine. Key features of this strategy enabled the synthesis of three additional iboga alkaloids, as well as an enantioselective total synthesis of (+)-ibogaine and the construction of four analogues. Biological testing revealed that the unnatural enantiomer of ibogaine does not produce ibogaine-like effects on cortical neuron growth, while (-)-10-fluoroibogamine exhibits exceptional psychoplastogenic properties and is a potent modulator of the serotonin transporter. This work provides a platform for accessing iboga alkaloids and congeners for further biological study.