A Route to Potent, Selective, and Biased Salvinorin Chemical Space.

A new chemical synthesis method produces salvinorin analogs that are more potent, selective, stable, and functionally biased than the natural compound salvinorin A. These analogs target the kappa-opioid receptor and could serve as templates for next-generation pain relievers, anti-itch treatments, and dissociative hallucinogens. The synthesis uses a special organocatalyst and a cobalt-catalyzed cycloaddition to efficiently create a library of these complex molecules, overcoming previous difficulties in modifying their structure.

Study at a glance

Abstract

The salvinorins serve as templates for next generation analgesics, antipruritics, and dissociative hallucinogens via selective and potent agonism of the kappa-opioid receptor (KOR). In contrast to most opioids, the salvinorins lack basic amines and bind with high affinity and selectivity via complex polyoxygenated scaffolds that have frustrated deep-seated modification by synthesis. Here we describe a short asymmetric synthesis that relies on a sterically confined organocatalyst to dissociate acidity from reactivity and effect Robinson annulation of an unactivated nucleophile/unstable electrophile pair. Combined with a cobalt-catalyzed polarized diene-alkyne cycloaddition, the route allows divergent access to a focused library of salvinorins. We appraise the synthesis by its generation of multiple analogs that exceed the potency, selectivity, stability, and functional bias of salvinorin A itself.