Sequential two electron photooxidation of t-amines: generation of a regiospecific iminium cation and its application in organic synthesis

PET activation of cyclic t-amines, utilizing 9, 10-dicyanonaphthalene (DCN) as light absorbing electron acceptor in aqueous acetonitrile solution, leads to the generation of iminium cation intermediate involving electron - proton - electron (E-P-E) transfer sequence. Iminium cation generation is found to be highly regiospecific and depends upon the kinetic acidity which is subject to the stereoelectronic factor of the α -C-H proton of the unymmetrical t-amines. Tetrahydro-1, 3-oxazines (6) are synthesized in complete regio-and stereoselective manner from the PET activation of the substrates of type 4. Nucleophilic alkylation of 6 by alkyl Grignard reagents provides cis- α, α'-dialkyl cyclic amines (8). Similarly, chiral perhydropyrido[2,1-b][1, 3, 4]-oxadiazinone (11) is synthesized as a precursor for the synthesis of optically active α-alkyl piperidines. Both enantiomers of hemlock alkaloid coniine (13) are also synthesized. Furthermore, to broaden the scope of these reactions, precursor 16 is designed for the synthesis of various α-amino acids and their N-alkyl derivatives

Generation and mesolytic dynamics of organoselenane and selenosilane radical ions: development of mechanistically interesting and synthetically useful chemistry

PET oxidation of PhSe-SePh and R-CH2-Se-R' generates an electrophilic selenium and carbocationic species, respectively. Similarly, one-electron reductive activations of R-CH2-Se-R' and R3-Si-SePh produces alkyl and alkyl silyl radicals, respectively. The possible structure of the reactive electrophilic selenium species is discussed and the fragmentation of -C-Se]•+ is found to be nucleophilic-assisted. These mechanistically interesting studies have been shown to be useful in initiating various synthetic reactions

?-Trimethylsilylmethylamine Radical Cation in the Synthesis of Cyclic Amines and Beyond

The evolution of chemistry associated with the photoinduced electron transfer (PET)-generated ?-trimethylsilylmethylamine radical cation cyclization to a tethered olefin to synthesize cyclic amine structural frame works is presented in chronological order. The importance of this interesting chemistry is demonstrated by the synthesis of several novel glycosidase inhibitors

Chiral 6-phenyl-2,3-bismethylenemethoxycarbonyl-[1,4]-dioxane as a designer synthon for an efficient and short synthesis of optically pure 2,6-dioxabicyclo[3.3.0]octane-3,7-dione

Chiral 6-phenyl-2,3-bismethylenemethoxycarbonyl-[1,4]-dioxane, synthesized by the PET cyclization of 8, has been used as a designer synthon for an efficient and short synthesis of optically pure 2,6-dioxabicyclo[3.3.0]octane-3,7-dione