Organoselenium-induced cyclizations in organic synthesis
作者:K.C. Nicolaou
DOI:10.1016/s0040-4020(01)93285-5
日期:——
A number of organoselenium reagents are introduced as efficient initiators of ringclosures leading from unsaturated substrates to lactones, cyclicethers, cyclic thioethers, N-heterocycles and carbocycles. These cyclizations often proceed with high ring selectivity and stereoselectivity and are accompanied by the incorporation of the phenylseleno group (PhSe) into the final product. Methods are described
Formation of electrophilic selenium species (PhSe+)by photo-oxidative (single-electron transfer) cleavage of diphenyl diselenide
作者:G. Pandey、V. Jayathirtha Rao、U. T. Bhalerao
DOI:10.1039/c39890000416
日期:——
Photosensitized (single-electrontransfer) cleavage of diphenyldiselenide to give electrophilicseleniumspecies (PhSe+) is reported.
报道了二苯二硒化物的光敏(单电子转移)裂解产生亲电硒物种(PhSe +)。
Photosensitized one-electron reductive cleavage of a carbon–selenium bond: a novel chemoselective deselenenylation and phenylselenenyl group transfer radical chain reaction
作者:Ganesh Pandey、K. S. Sesha Poleswara Rao、B. B. V. Soma Sekhar
DOI:10.1039/c39930001636
日期:——
A novel photosensitized one-electron reduction of organoselenium compounds leading to chemoselective deselenenylation and phenylselenyl group transfer radical chain processes is reported.
报告了一种新型光敏化单电子还原有机硒化合物,导致化学选择性去硒化和苯基硒基转移自由基链过程。
Photoinduced Electron Transfer Initiated Activation of Organoselenium Substrates as Carbocation Equivalents: Sequential One-Pot Selenylation and Deselenylation Reaction
作者:Ganesh Pandey、B. B. V. Soma Sekhar
DOI:10.1021/jo00103a031
日期:1994.12
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET activation of organoselenium substrates. Fluorescence quenching of (DCN)-D-1* by a number of organoselenium compounds (RCH(2)SeR', 1-4), correlation of the fluorescence quenching rate constants with the oxidation potentials of 1-4, and the dependence of photodissociation quantum yields of 1-4 on their concentration suggests the occurrence of electron transfer processes between (DCN)-D-1* and 1-4. Steady-state photolysis of 1-4 in the presence of (DCN)-D-1* leads to the efficient one-electron oxidative heterolytic dissociation of the carbon-selenium bond to produce the carbocation (RCH(2)(+) or equivalent) and radical-centered selenium species (R'Se-.) via the intermediacy of cation-radical [(RCH(2)SeR')(+.)]. Nucleophilic assistance in the fragmentation of (RCH(2)SeR')(+.) by methanol has been suggested on the basis of products obtained from the control PET reaction of neopentyl phenyl selenide (8). The synthetic utility of these findings has been demonstrated for the deselenylation (Table 4) as well as one-spot sequential selenylation-deselenylation (Table 5) reactions.
Photoinduced single electron transfer initiated heterolytic carbon-selenium bond dissociation. Sequential one-pot selenenylation and deselenenylation reaction
作者:Ganesh Pandey、B. B. V. Soma Sekhar、U. T. Bhalerao