52881-68-2Relevant academic research and scientific papers
A new chiral organosulfur catalyst for highly stereoselective synthesis of epoxides
Gui, Yuan,Li, Jian,Guo, Chang-Shan,Li, Xin-Liang,Lu, Zhi-Feng,Huang, Zhi-Zhen
supporting information; experimental part, p. 2483 - 2487 (2009/09/08)
A new chrial organosulfide was synthesized through an unexpected Wagner-Meerwein rearrangement. This organosulfide could catalyze the epoxidation reaction of various aromatic aldehydes smoothly with benzyl bromide to give trans-diaryl epoxides in satisfactory yields (60-84%) with excellent diastereoselectivities (trans:cis=95:5-100:0) and good to excellent enantioselectivities (86-96% ee).
Highly stereoselective synthesis of trans-diaryl epoxides via semi-stabilised telluronium ylide
Wang, Lei,Huang, Zhizhen
, p. 305 - 306 (2007/10/03)
Benzyldibutyltelluronium bromide can react with LDA to form benzyldibutyltelluronium ylide in situ, followed by the reaction with aromatic aldehydes, developed a novel method for the stereoselective synthesis of trans-diaryl epoxides.
Experimental evidence for multiple oxidation pathways in the (salen)Mn-catalyzed epoxidation of alkenes
Linde, Christian,Koliai, Nordine,Norrby, Per-Ola,Akermark, Bjoern
, p. 2568 - 2573 (2007/10/03)
The substrate electronic effects on the selectivity in the catalytic epoxidation of para-substituted cis stilbenes 2a-i were investigated by using (R,R)-[N,N′-bis(3,5-di-tBu-salicylidene)-1,2-cyclohexanediamine] manganese(III) chloride 1 in benzene as the catalyst with iodosobenzene as the terminal oxidant. A Hammett study of the selectivity results reveals a stronger electrophilic character than previously assumed in the (salen)Mn-catalyzed reaction. In general, the best correlations with the experimental values were obtained by using the Hammett σ+ values, which gave ρ = -1.37 for the rate of cisepoxide formation and ρ = -0.43 for the rate of the stepwise process leading to the corresponding trans product. The reaction involves two separate pathways as indicated also by the competitive breakdown of the intermediate on the path to trans epoxide for methoxy-substituted substrates. The asynchronicity in the concerted pathway leading to cis epoxide is apparent for 4-methoxy-4′-nitrostilbene, which yields cis epoxide with 75% ee entirely as a result of electronic effects.
KINETICS OF THE N OXIDATION OF SOME COMPOUNDS OF THE PYRIDINE SERIES WITH PERBENZOIC ACID IN CHLOROFORM AND AQUEOUS DIOXANE
Lohkov, R.E.
, p. 264 - 271 (2007/10/02)
A comparative study of the kinetics of the N oxidation of 19 derivatives of the pyridine series with perbenzoic acid in choroform and aqueous dioxane at 20, 25, 30, and 35 deg C was made.The rate constants, the parameters of the Arrhenius equation, and the activation energies of the N oxidation of the indicated monoazines were determined.The scale of the reactivities of the derivatives of the pyridine series was calculated within the framework of the Pearson hard-soft acid-base concept.
