Development of a Novel Chiral Spiro Ligand Bearing Oxazoline.

Abstract

Abstract The synthesis of bis(oxazoline) ligand 1 bearing a spiro skeleton is achieved via double ring-closing metathesis (RCM) of tetraene 2 and subsequent oxazoline ring formation using N-bromosuccinimide (NBS). The Cu-spiro bis(oxazoline) complexes prepared from 1 and Cu(OTf)2 or Cu(OAc)2 act efficiently as chiral catalysts for promoting carbonyl-ene reactions or Henry reactions with good enantiocontrol.