Synthesis of chiral 1-substituted tetrahydroisoquinolines by the intramolecular 1,3-chirality transfer reaction catalyzed by Bi(OTf)_3

摘要

The intramolecular 1,3-chirality transfer reaction of chiral amino alcohols 1 with 99% ee was developed to construct chiral 1-substituted tetrahydroisoquinoline 2. Bi(OTf)_3 (10 mol %)-catalyzed cyclization of 1 (R = H) afforded (S)-1-(E)-propenyl tetrahydroisoquinoline 2 (R = H) in 83% yield with a ratio of 98:2. The stereochemistry at the newly formed chiral center was produced by a syn S_N2′-type process. In this reaction, the substituent on the benzene ring of 1 significantly affected the reactivities and selectivities. A plausible reaction mechanism was proposed.