Photochemically-induced C–C bond formation between tertiary amines and nitrones

Abstract

Photoexcited nitrones serve as excellent electron acceptors as well as radical acceptors in the presence of tertiary amines to give β-amino hydroxylamines via photochemically-induced direct sp³ C–H functionalization of the tertiary amines. The combined use of an organophotosensitizer and photoirradiation was highly effective in accelerating addition reactions. Several nitrones and tertiary amines were successfully utilized to give β-amino hydroxylamines in good yield. Highly regioselective generation of primary α-aminoalkyl radicals based on Lewis's stereoelectronic rule and diastereoselective addition reactions of primary α-aminoalkyl radicals with nitrones were successfully achieved. Furthermore, a highly diastereoselective reaction of an α-aminoalkyl radical with a chiral (E)-geometry-fixed α-alkoxycarbonylnitrone was performed.