Taming Radical Pairs in the Crystalline Solid State: Discovery and Total Synthesis of Psychotriadine.

Solid-state photodecarbonylation is an attractive but underutilized methodology to forge hindered C-C bonds in complex molecules. This study discloses the use of this reaction to assemble the vicinal quaternary stereocenter motif present in bis(cyclotryptamine) alkaloids. Our strategy was enabled by experimental and computational investigations of the role of substrate conformation on the success or failure of the solid-state photodecarbonylation reaction. This informed a crystal engineering strategy to optimize the key step of the total synthesis. Ultimately, this endeavor culminated in the successful synthesis of the bis(cyclotryptamine) alkaloid "psychotriadine," which features the elusive piperidinoindoline framework. Psychotriadine, a previously unknown compound, was identified in the extracts of the flower Psychotria colorata, suggesting it is a naturally occurring metabolite.

Discovery and Total Synthesis of a Bis(cyclotryptamine) Alkaloid Bearing the Elusive Piperidinoindoline Scaffold.

Bis(cyclotryptamine) alkaloids have been popular topics of study for many decades. Five possible scaffolds for bis(cyclotryptamine) alkaloids were originally postulated in the 1950s, but only four of these scaffolds have been observed in natural products to date. We describe synthetic access to the elusive fifth scaffold, the piperidinoindoline, through syntheses of compounds now termed "dihydropsychotriadine" and "psychotriadine". The latter of these compounds was subsequently identified in extracts of the flower Psychotria colorata. Our synthetic route features a stereospecific solid-state photodecarbonylation reaction to introduce the key vicinal quaternary stereocenters.

Treating a Global Health Crisis with a Dose of Synthetic Chemistry.

The SARS-CoV-2 pandemic has prompted scientists from many disciplines to work collaboratively toward an effective response. As academic synthetic chemists, we examine how best to contribute to this ongoing effort.