Catalytic Sc(OTf)3 mediated direct asymmetric aldol reaction of (-)-menthyl isothiocyanatoacetate with aldehydes by using (-)-menthol as chiral auxiliary

This method involves the direct asymmetric aldol reaction of (-)-menthyl isothiocyanatoacetate 5 with a variety of substituted aromatic aldehydes, which offers a convenient method for the synthesis of intermediate containing biologically relevant alpha-amino beta-hydroxyl groups in oxazolidine ring. In this methodology, the products show remarkable diastereoselectivity using Sc(OTf)(3) as a catalyst and easily accessible (-)-menthol as a chiral auxiliary. This approach includes some important aspects such as mild reaction conditions, high yields, and excellent diastereoselectivity with a number of substituted aromatic aldehydes. The optimization and effect of different catalysts were studied at different reaction conditions and it is found that Sc(OTf)(3) shows excellent diastereoselectivity at -45 degrees C.

Automated summary

This method utilizes Sc(OTf)(3) as a catalyst and (-)-menthol as a chiral auxiliary to achieve remarkable diastereoselectivity in the asymmetric aldol reaction. It offers mild reaction conditions, high yields, and excellent diastereoselectivity with a variety of substituted aromatic aldehydes. Sc(OTf)(3) demonstrates excellent diastereoselectivity at -45 degrees C under different reaction conditions.