A short synthesis of apoyohimbines via a sulfolene based intramolecular Diels-Alder reaction

Article abstract of DOI:10.1016/S0040-4039(00)79968-0

Allo-apoyohimbine and apoyohimbine have been synthesized in a short sequence of high yielding, stereoselective steps. The key step is an intramolecular Diels-Alder reaction, which under kinetically controlled conditions provides the required hexahydroisoquinoline D/E-ring intermediate, but under thermodynamic control gives a hydroisoindole system, via a conjugated diene.