Binaphthol-derived titanium µ-oxo complex: a new type of asymmetric catalyst for carbonyl-ene reaction with glyoxylate

Abstract

The binaphthol (binol)-derived chiral titanium µ-oxo complex O is obtained accidentally upon toluene azetropy from a solution of binol and (PrⁱO)₂ TiCl₂ after filtration of ms 4 Å and shown to be an efficient asymmetric catalyst for the glyoxylate-ene reaction with α-methylstyrene to give 98.7% entaniomeric excess and 88% yield even by the use of 0.2 mol% of the complex O.