Birch/Cope Sequence to Address Challenges in Natural Product Synthesis

Jisun Lee

Over the years, natural product synthesis has drawn significant interest in the field of organic chemistry. Natural products have proven valuable as lead compounds for new drugs. Many natural products contain chiral quarternary carbons that are difficult to synthesize in the laboratory. We have recently developed a new and efficient stereoselective method to synthesize quaternary carbons. The process employs a sequence with an enantioselective Birch reduction-allylation, followed by the Cope rearrangement (Scheme 1).

After further investigation of this synthetic method, the procedure will be applied to the enantioselective synthesis of (+)-lycoramine (Figure 1). (+)-Lycoramine is an analog of (-)-galanthamine, which was recently approved for the treatment of Alzheimer’s disease (Figure 2). Furthermore, (+)-lycoramine has been found to have a similar role as (-)-galanthamine in the inhibition of acetylcholinesterase. However, since there is currently no enantioselective synthesis of (+)-lycoramine, the Birch/Cope sequence will provide a powerful example of the application of the Birch/Cope sequence to address challenges in natural product synthesis.