Asymmetric hydrogenation of 3-methyl-fumaric and maleic ester monoaldehydes protected as neph-derived oxazolidines
摘要:
The hydrogenation of 3-methyl-fumaric and maleic ester mono aldehydes protected as oxazolidines of nor-ephedrine (NEPH) derivation has been studied. This transformation takes place with moderate to good pi-face stereodifferentiation and allows the preparation of non-racemic 3-methyl-succinaldehydic acid methyl ester (1, R = Me). The factors dictating the diastereocontrol are discussed.