Ir-catalyzed allylic amination/ring-closing metathesis: A new route to enantioselective synthesis of cyclic beta-amino alcohol derivatives

Abstract

[GRAPHICS] Ir-catalyzed allylic aminations of (E)-4-benzyloxy-2-butenyl methyl carbonate with benzylan-fine using Feringa's (S-a,S-c,S-c)-phosphoramidite as a chiral ligand afforded linear-aminated achiral product N,O-dibenzyl-4-amino-2-buten-l-oI regioselectively (linearibranched = >99/1), whereas the (E)-5benz),Ioxy-2-pentenyl methyl carbonate showed completely opposite regioselectivity (linearlbranched = > 1/99) and afforded the optically active. (3R)-N,O-dibenzylated 3-amino-1-penten-5-ol with very high enantioselectivity (96% ee), which was used as a key intermediate for the effective synthesis of various cyclic beta-amino alcohol derivatives through ring-closing metathesis in high yields.