Synthesis of the 1-phenethyltetrahydroisoquinoline alkaloids (+)-dysoxyline, (+)-colchiethanamine, and (+)-colchiethine.

Asymmetric total syntheses of the 1-phenethyl-1,2,3,4-tetrahydroisoquinoline alkaloids (+)-dysoxyline (1), (+)-colchiethanamine (2), and (+)-colchiethine (3) 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 1-3.