Enantioselective catalysis of Claisen rearrangement by DABNTf–Pd(II) complex

Two types of palladium complexes, cationic ( R ) - BINAP – Pd 2 + ( SbF 6 - ) 2 and neutral (R)-DABNTf–Pd(CH3CN)2 were examined as chiral catalysts for enantioselective Claisen rearrangement. DABNTf–Pd(CH3CN)2 complex gave high enantio- and anti-diastereoselectivity, and good yield. This Claisen rearrangement should proceed via six-membered boat transition state through bi-dentate coordination to the Pd catalyst.