Synthesis and resolution of 1-(α-pyrrolidinylbenzyl)-2-naphthol and its application in the resolution of 2,2 < sup > ′ < /sup > -dihydroxy-1,1 < sup > ′ < /sup > -binaphthyl

Abstract

1-(α-Pyrrolidinylbenzyl)-2-naphthol 2 is easily prepared in 95% yield using benzaldehyde, 2-naphthol and pyrrolidine in ethanol at 78°C. It is resolved using inexpensive L-(+)-tartaric acid to obtain non-racemic samples that can be readily purified to enantiomeric purity through preparation of hydrogen bonded aggregates. The homochiral 1-(α-pyrrolidinylbenzyl)-2- naphthol 2 is useful in the resolution of racemic 2,2′- dihydroxy-1,1′-binaphthyl (BINOL) 3 via preparation of the corresponding diastereomeric borate complexes using B(OH)3. © 2004 Elsevier Ltd. All rights reserved.