Amine fragment stereochemistry

Photochemical dehydrofragmentation has also been observed by Whitten et al. [16, 17] in PET reactions of aminoalcohols. The reaction is restricted to the geminate pair and the complimentary roles of reduced acceptor and oxidized donor facilitate chemical reaction in competition with back ET. The rapid fragmentation is dependent on the acceptor anion-radical induced deprotonation of the donor cation radical in the contact ion-pair and is strongly dependent on the structure of A [16]. The chemical transformation converts the aminoalcohol into the free amine, aldehyde and reduced electron acceptor. The efficiency of the PET induced fragmentation is affected by the stereochemistry of the aminoalcohol as well as the solvent [18]. Both the thioindigo (TI) and dicyanoanthracene (DCA) sensitized reactions are more efficient in nonpolar solvents such as benzene and... 

A distinction was made between two proposed mechanisms for the fragmentation of an oxaziridine, using a combination of the primary kinetic isotope effect and stereochemistry [13], Amines can behave as bases and attack at hydrogen, or they can be nucleophiles and attack at carbon or nitrogen E2 and 8, 2 reactions are examples. In Equation 4.36, a tertiary amine (brucine) is shown in the role of base in a step resembling an E2 reaction. In Equation 4.37, the amine is shown attacking the nitrogen... 

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