Dihydroxylation of olefins catalyzed by zeolite-confined osmium(0) nanoclusters: an efficient and reusable method for the preparation of 1,2-cis-diols

Generating and optimizing the catalytic activity in UiO-66 for aerobic oxidation of alkenes by post-synthetic exchange Ti atoms combined with ligand substitution

“…These observations are in agreement with previous reports that have reported a smaller Lennard-Jones kinetic diameter for trans-stilbene (7.1 Å) compared with the bulkier cis isomer (7.8 Å). 78 Alternatively, the possibility that the cis isomer exhibits lower reactivity respect to the trans isomer cannot be ruled out. Thus, in contrast to the case of cyclooctene, where some degree of conversion occurs in the liquid phase, the lack of reactivity of cis-stilbene indicates that, for conjugated alkenes, the contribution of oxidation outside the pores should negligible.…”

Cu(II)-Schiff base covalently anchored to MIL-125(Ti)-NH2 as heterogeneous catalyst for oxidation reactions

“…This distinctive reactivity is compatible with the occurrence of the reaction, at least partially, inside the pores. In this way, the higher reactivity of trans-stilbene would be a consequence of its faster diffusion through the pores, due to its smaller Lennard-Jones kinetic diameter compared (4.9 Å) to the bulkier cis isomer (7.8 Å) 53. Time-conversion plot for the epoxidation of trans-(■) and cis-(○) stilbene catalyzed by MIL-125 (Ti)-NH2-Sal-Cu.…”

A mild access to chiral syn 1,2-diaryl glycols by stereoselective ring opening of ortho substituted trans 2,3-diaryl-oxiranes using Amberlyst 15 in H2O/THF system

“…This is highly pointed out by the literature on immobilization of the catalyst on suitable inorganic or organic supports as polymers, 25 dendrimers, 26 ionexchange resins, 27 silica gels, 28 hydroxyapatites, 29 fullerenes, 30 mesoporous and microporous solids. 31 In particular, substituted stilbene derivatives are rarely encountered. 32 Thus a series of new enantioenriched 2-aryl-3-phenyloxiranes was prepared by asymmetric sulfur ylide mediated epoxidation of aldehydes, 33 using Isothiocineole as chiral precursor, which is readily available in both enantiomeric forms and has been recently shown to be highly efficient in epoxidation and aziridination reactions, with high levels of enantioselectivity.…”