step of these reactions. Electron-withdrawing as well as -donating substituents at the phenyl group increase the reaction rate. Quantum chemical computations did not reveal any correlation between either the enthalpy or Gibbs free energy of the N–C bond cleavage step and the experimentally determined first-order rate constants. Instead, the structural difference between the excitedstate generated by
Iron-Catalysed Reduction of Olefins using a Borohydride Reagent
作者:Tom S. Carter、Léa Guiet、Dominik J. Frank、James West、Stephen P. Thomas
DOI:10.1002/adsc.201200577
日期:2013.3.25
The iron‐catalysedreduction of olefins has been achieved using a simple iron salt and sodium triethylborohydride. A wide range of mono‐ and trans‐1,2‐disubstituted alkenes have been reduced (91–100%) using 25 mol% iron(II) triflate, 1 mol% N‐methyl‐2‐pyrrolidinone and 4 equivalents of sodium triethylborohydride. The reduction of alkynes to alkanes is also reported (up to 84%). Significantly, the reduction
is important in organic synthesis for the preparation of natural products, organic materials and polymers and so on. An efficient and mild reductive homocoupling of arylmethylhalides is now described. Treatment of various benzylic halides in the presence of zero valent iron nanoparticles (nZVI) and a catalytic amount of CuBr in air and water at room temperature afforded 1,2-diarylethanes in excellent
Les composés d'insertion du graphite comme précurseurs de métaux finement divisés
作者:P. Marceau、F. Beguin、G. Guillaumet
DOI:10.1016/0022-328x(88)80050-0
日期:1988.3
reduction of a nickel salt by the intercalation compound KC8, results in highly dispersed nickel on graphite, which has been used as a coupling reagent for benzylchloride. The yield and the selectivity of the reaction were slightly improved when nickel-copper bimetallic clusters were used. The properties of these mixtures are illustrated by the coupling of various substituted benzyl halides. Functional
Substituent Effects on the Photocleavage of Benzyl−Sulfur Bonds. Observation of the “<i>Meta</i> Effect”
作者:Steven A. Fleming、Anton W. Jensen
DOI:10.1021/jo9606923
日期:1996.1.1
substituted benzyl phenyl sulide. The effect of oxygen on quantum yields is best observed after samples are thoroughly outgassed with consecutive freeze-pump-thaw cycles. It is shown that oxygen diminishes the substituenteffect. Upon photolysis of the outgassed samples, the meta-substituted derivatives showed more significant variances than the para derivatives. The meta derivatives are most efficiently