Lipase-catalysed resolution of 3,3′-bi-indolizines: The first preparative access to enantiomerically pure samples

The lipase-catalysed kinetic resolution of the axially chiral 3,3′-bis[1-(2-hydroxyethyl)-2-phenylindolizine] [(±)-1a] and the corresponding 3-hydroxypropyl derivative (±)-1b by acylation with vinyl acetate in the presence of lipases from different origins has been investigated. For the first time, enantiomerically pure 3,3′-biindolizine derivatives were obtained on a preparative scale by careful monitoring of the conversion.