Abstract
The excited state chemistry of iminium salts has been explored in an attempt to uncover new organic photochemical processes. Results from these studies demonstrate that electron-rich olefins undergo efficient photoaddition to iminium salts leading to the formation of [HAA]-aminoethers when irradiations are conducted in alcoholic solvents. This novel carbon-carbon bond forming reaction can be nicely rationalized using mechanisms in which electron transfer from olefin to singlet excited iminium salt occurs initially to generate radical cation-radical pairs followed by regiospecific alcohol addition to the positively charge fragment and radical coupling. Evidence for this mechanism is provided by the contrastingly different results obtained from olefin-iminium slat photoreactions when electron-poor olefins are employed. Quantitative photochemical and photophysical data obtained further support operation of the electron transfer mechanism in both olefin addition and fluorescence quenching processes. Intramolecular counterparts of this excited state reaction serve to exemplify its synthetic potential. Irradiation of aqueous or methanolic solutions of N-allyliminium slats, for example, leads to production of pyrrolidinyl alcohols or ether. Furthermore, N-alkenyliminium salt photocyclization reactions are useful in the construction of nitrogen containing bridged- and fused-bicyclic substances. The mechanistic and synthetic aspects of these reactions will be discussed in detail.
Stavinoha, Jerome Leonard (1979). The photochemistry of iminium salts : novel reactions with olefins. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -176530.