Ryanoids and related compounds — Chemoselective electrocatalytic hydrogenation of alkyl α-pyrrole carboxylates: Selective hydrogenation of ryanodine

Abstract

A study of the electrocatalytic hydrogenation (ECH) process of pyrrole and different alkyl pyrrole-2-carboxylates is presented. Once hydrogenated, the alkyl pyrrole-2-carboxylate becomes an ester of proline, an important natural amino acid. The process is chemoselective to the pyrrole ring. Ryanodine is a natural ryanoid known to be biologically active. The tetrahydroryanodine derivative thus obtained may now represent a molecule of high biological interest. The hydrogenation of ryanodine is possible with electrocatalytic and catalytic processes. In both cases the reaction is not diastereoselective.Key words: electrocatalytic hydrogenation, proline esters, ryanodine, tetrahydroryanodine.