Synthesis of the 1‑Phenethyltetrahydroisoquinoline Alkaloids (+)-Dysoxyline, (+)-Colchiethanamine, and (+)-Colchiethine

Abstract

Asymmetric total syntheses of the 1-phenethyl-1,2,3,4-tetrahydroisoquinoline alkaloids (+)-dysoxyline (<b>1</b>), (+)-colchiethanamine (<b>2</b>), and (+)-colchiethine (<b>3</b>) are described. In the synthetic routes, coupling of a key, enatiomerically pure 1-(sulfonylmethyl)­tetrahydroisoquinoline with aromatic aldehydes, performed by using the Julia–Kocienski reaction, afforded the corresponding 1-(β-styryl)-substituted tetrahydroisoquinolines with complete retention of the absolute configuration at the C1 carbon atom. Functionalization of the products generated in these processes by using four- or five-step sequences gave the target alkaloids <b>1</b>–<b>3</b>