REGENERATION OF 2,2`-CYCLOPROPYLIDENE-BIS(OXAZOLINES)

摘要

The present invention provides a method for regeneration of chiral 2,2'-cyclopropylidene-bis(oxazolines), such as (3&R, 3'aR,8aS,8'aS)-2,2'-cyclopropylidenebis-[3a,8a]-dihydro-8H-indeno-[1,2-d]-oxazole and (45,4'5,5R,5'R)-2,2'-cyclopropy-lidenebis-4,5-diphenyldihydro-4,5-oxazole, used as a part of complex catalysts for e.g. stereoselective addition reactions, from the reaction mixtures, by selective sorption of 2,2'-cyclopropylidene-bis(oxazolines) on a sorbent, such as silica gel, isolation of the sorbent from reaction mixture, desorption of 2,2'-cyclopropylidene-bis(oxazolines) from the sorbent with suitable organic solvent and final recovery of 2,2'-cyclopropylidene-bis(oxazolines) from the organic solvent used for desorption process. Catalytic quality of recovered compounds does not differ from those in freshly prepared catalysts.