Synthetic Perspectives of Photoinduced Electron Transfer Generated Amine Radical Cations

"True sensitized" photo-SET reactions from a variety of tertiary amines and singlet excited cyanoarenes [mainly 1,4-dicyanonaphthalene and 9,10-dicyanoanthracene] have been observed. The free amine radical cation, formed via a solvent separated ion pair, undergoes efficient deprotonation-desilylation at the carbon adjacent to nitrogen. The synthetic usefulness of this step is demonstrated in generating reactive intermediates such as nitrones, iminium cations, α-amino radicals and azomethine ylides depending on the substrates and reaction medium. 1. Introduction 2. Generation of Cyclic Nitrones: A Versatile 1,3-Dipole 3. Generation of Regiospecific Iminium Cation 3.1. Synthesis of Oxaazabicyclo[m.n.o]alkanes and Related Compounds 3.2. Stereoselective Synthesis and Utilization of Tetrahydro-1,3-oxazines 3.3. SET Promoted Photo N-Debenzylation and N-Dealkylation 4. Generation and Reactivity of α-Amino Radical (or Equivalent) 5. Generation of Non-Stabilized Azomethine Ylides 6. Conclusion