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′-cyclopropylidenebis-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.

主权项

1. A process for regeneration of chiral 2,2′-cyclopropylidene-bis(oxazoline) from a reaction mixture of a catalytic organic reaction, in which said 2,2′-cyclopropylidene-bis(oxazoline) is used as ligand part of a complex catalyst, comprising the following steps of: separation of 2,2′-cyclopropylidene-bis(oxazoline) from the reaction mixture by sorption of 2,2′-cyclopropylidene-bis(oxazoline) on a sorbent; isolation of the sorbent with sorbed 2,2′-cyclopropylidene-bis(oxazoline) from reaction mixture; desorption of 2,2′-cyclopropylidene-bis(oxazoline) from the sorbent; recovery of 2,2′-cyclopropylidene-bis(oxazoline) from organic solvent used for desorption procedure, and the 2,2′-cyclopropylidene-bis(oxazoline) is (3aR,3′aR,8aS,8′aS)-2,2′-cyclopropylidenebis-[3a,8a]-dihydro-8H-indeno-[1,2-d]-oxazole.