Addition of Amines Hydroaminomethylation or Amides

Hydroaminomethylation reactions can be accomplished by addition of nucleophilic a-amino alkyl radicals (generated from amines) onto electron-deficient alkenes [7, 21], Amines have a low oxidation potential, and are easily oxidized by excited aromatic ketones bearing electron-donating substituents (e.g., Michler s ketone) or 

Another approach involves the use of an electron-poor olefin acting both as an absorbing electron acceptor and as a radical trap. In this case, a PET reaction between a cyclohexenone derivative and a silylated amine led to a radical ion pair. Desilylation of the silyl amine radical cation intermediate in polar protic solvent (e.g., MeOH) and subsequent aminoalkyl radical attack onto the enone radical anion yielded the alkylated cyclohexanones [23]. 

In rare instances, hydroaminomethylation can occur by using electron-rich alkenes such as styrene derivatives. Thus, 1-phenylpropene added Me3N regioselec-tively to form N,N-dimethyl-2-phenylbutan-l-amine upon excitation via a styrene-amine exciplex [24]. 

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