Iminiumverbindungen vom Typ 1 reagieren in [2⊕ + 1]‐Cycloadditionsreaktionen nur mit dem nucleophilen Carben 2b, nicht mit Methylencarben (2a). Demgegenüber addiert sich 2a an das Enamin 5. Nur sterisch wenig anspruchsvolle Carbiminium‐Strukturen können mit 2,3‐Dimethylbutadien (10) zu “Diels‐Alder‐Addukten” 11 umgesetzt werden.
Allylstannane photoadditions to iminium salts. Efficiencies of sequential electron transfer destannation versus desilylation pathways
作者:Robert M. Borg、Patrick S. Mariano
DOI:10.1016/s0040-4039(00)84651-1
日期:1986.1
Electrontransfer induced, photoadditions of allyltins to 1-methyl-2-phenyl-1-pyrrolinium perchlorates have been probed. The quantum efficiencies of these processes are larger that for photoaddition of the corresponding allylsilane.
Arene-iminium salt electron-transfer photochemistry. Mechanistically interesting photoaddition processes
作者:Robert M. Borg、Robert O. Heuckeroth、Alexander J. Y. Lan、Suzanne L. Quillen、Patrick S. Mariano
DOI:10.1021/ja00243a028
日期:1987.4
Studies of the electron-transfer photochemistry of arene-iminium saltsystems have been explored. Fluorescence quenching investigations have demonstrated that a series of arenes including substituted toluenes and benzenes quench the fluorescence of a variety of 2-aryl-1-pyrrolinium perchlorates. Quenching rate constants in these cases correlate with the ..delta..G/sub SET/ values as expected for quenching
Photochemistry of iminium salts in the presence of N-electron donating alcohols and ethers
作者:Jerome Stavinoha、Elliott Bay、Andrea Leone、Patrick S. Mariano
DOI:10.1016/s0040-4039(00)78713-2
日期:1980.1
alcohols and ethers containing α-hydrogens leads to production of addition products. In addition, alcohols and ethers having low ionization potentials and α-hydrogens serve as efficient quenchers of fluorescence from 2-phenyl-1-pyrrolinium salts. Deuterium isotope effects on fluorescence quenching rate constants appear to implicate electrontransfer mechanisms in photoaddition and quenching pathways.
The photolysis of 1-methyl-2-phenyl-1-pyrrolinium perchlorate (1) with a 3-butenoate anion in an aqueous solution efficiently gives a 2-allylpyrrolidine adduct. Mechanistic studies demonstrate that the photo-reaction is induced by a one-electron transfer from 3-butenoate to the singlet excited-state of 1.