The synthesis of a novel non-C-2 symmetric H-4-BINOL ligand and its application to titanium-catalyzed enantioselective addition of diethylzinc to aldehydes

摘要

The synthesis of the novel non-C-2 symmetric ligand (R)-5,6,7,8-tetrahydro-1,1'-binaphthol has been achieved via partial reduction of 2,2'-bis(methoxymethoxy)-1,1'-binaphthyl with Raney Ni-Al alloy in dilute aqueous NaOH solution followed by hydrolysis with HCl. Its titanium complex was found to be an effective catalyst in the asymmetric addition of diethylzinc to a variety of aldehydes, leading to the formation of secondary alcohols in high yields with good to excellent enantioselectivities. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 21]