Visible-Light-Promoted α-C(sp~3)-H Functionalization Of Amines

Nitrogen-containing organic compounds are important compounds,which are widely used in natural products,medicine,pesticide and functional materials.Therefore,it is of great significance to develop a green and efficient method for nitrogen-containing organic compound transformation.Visible-light-drivenα-C（sp³）-H functionalization of amines is an important method for the transformation of nitrogen-containing organic compounds,and has been obtained great progress in recent years.However,these methods usually require the use of visible-light catalysts and strong oxidants.In this work,a visible-light-driven,photocatalyst-free,water-and air-promotedα-C（sp³）-H functionalization of amines is described.Theα-C（sp³）-H functionalization of N-aryl trifluoroquinoline with potassium allyltrifluoroborate was selected as model reaction to optimize the reaction conditions such as light source,solvent,reaction time,etc.The optimal reaction conditions were as follows:N-aryl tetrahydro isoquinoline（0.2 mmol）,potassium allyltrifluoroborate（0.4 mmol）,Me CN/THF/H₂O（v/v/v=2:1:2）as solvent,6×3 W blue LEDs as light source,at room temperature in air for 12 h.This reaction features catalyst-free,good functional group tolerance,simple operation procedure,and green reaction conditions.Theα-C（sp³）-H functionalization of amines with various nucleophiles（including potassium allyltrifluoroborates,allylic pinacolboronic esters,nitroalkanes,phosphonite esters,trimethylsilanes,acetone,etc.）proceed smoothly to afford the corresponding products in37%-89%yields.The obtainedα-substituted amine products were characterized by the nuclear magnetic resonance spectroscopy（¹H-NMR）and the nuclear magnetic resonance carbon spectrometry(¹³C-NMR).