A novel approach towards the synthesis of an oxazine scaffold using scandium trifluoromethanesulfonate catalysed N, O-acetal and olefin cyclisation sequence

Abstract

A novel approach to [1,3]oxazin-1-ones from 1,1-disubstituted alkene and N,O-acetals through scandium trifluoromethanesulfonate as catalyst in dichloroethane at 60 °C. The structure of this product is easily accessible. This protocol merits several advantages, such as very gentle conditions, cheap starting materials, and high yields. Altogether, 22 cases were investigated, and all the products were confirmed by spectrum methods. Three compounds were performed single crystal diffraction. The diastereochemistry was also studied in several cases.