S-Benzyl-N,N'-diphenyl Isothiouronium Iodide as an Efficient Organocatalyst for the Transfer Hydrogenation of 1,4-Benzoxazines

摘要

This study reports on the isothiouronium salt catalyzed transfer hydrogenation of various 3-substituted-2H-1,4-benzoxazines,with Hantzsch esters as a hydrogen source.Transfer hydrogenation of 1,4-benzoxazines has been successfully carried out with small amount of 1 mol% S-benzyl-N,N'-diphenyl isothiouronium iodide as a catalyst.Various 3,4-dihydro-2H-1,4-benzoxazines were obtained in quantitative yield at room temperature.