Structure investigation of Ti-IV-BODOLates involved in the catalytic asymmetric reduction of ketones using catecholborane

摘要

The complexes formed by the reaction of [Ti(OiPr)(4)] and bicyclo-octanediols (BODOLs) 1 and 2 (1:1) are useful as chiral catalysts in asymmetric reductions and were investigated by H-1 NMR spectroscopy and computational methods. A consistent picture emerged of head-to-tail dimers being kept together via a Ti-O-Ti-O mu-oxo bridge similar to the Ti-tartrates but different from the corresponding Ti-BINOLates and Ti-TADDOLates.