Enantiomeric resolution by lipase-catalysed esterification of a trans-5,6-dihydro-1,10-phenanthroline possessing helical and central chirality

Lipase-catalysed enantioselective esterification was carried out to obtain the kinetic resolution of (±)-trans-5-hydroxy-6-methoxy-1,10-phenanthroline (±)-1b. Different lipases from Candida cylindracea, Candida antarctica, Rhizomucor miehei, Pseudomonas fluorescens and Pseudomonas cepacia were tested in an unusual methanol/vinyl acetate (8:92 v/v) reaction mixture P. fluorescens lipase showed good enantiodifferentiation (E = 48) and allowed us to prepare both enantiomers (+)-(5S,6S,M)-1b and (-)-(5R,6R,P)-1b with an enantiomeric excess of >97%.