71912-37-3Relevant academic research and scientific papers
Preparative and mechanistic studies toward the rational development of catalytic, enantioselective selenoetherification reactions
Denmark, Scott E.,Kalyani, Dipannita,Collins, William R.
supporting information; experimental part, p. 15752 - 15765 (2011/02/22)
A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Bronsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1′-binaphthalene-2,2′-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.
Reaction of Areneselenyl Chlorides and alkenes. An example of Nucleophilic Displacement at Bivalent Selenium
Schmid, George H.,Garratt, Dennis G.
, p. 4169 - 4172 (2007/10/02)
The effect of substituents in the phenyl ring of both the electrophile and the alkene has been studied in the reaction of areneselenyl chlorides and (E)- and (Z)-1-phenylpropenes.Electron-donating groups in both phenyl rings enhance the rate of reaction.Viewing this reaction as a nucleophilic displacement at bivalent selenium leads to a model that allows the possibility of reaction by a continuum of mechanisms.These mechanisms differ only in the relative amounts of C-Se bond making and Se-Cl bond breaking in the rate-determining transition state.From our data, it is concluded that C-Se bond making lags behind Se-Cl bond breaking in the rate determining transition state.
