25139-43-9Relevant articles and documents
MISE EN EVIDENCE DU MECANISME "SN2 (INTERMEDIAIRE)" DANS DES SOLVOLYSES DE TOSYLATES SECONDAIRES ENCOMBRES. ABSENCE DE CORRESPONDANCE VITESSES-PRODUITS
Laureillard, J.,Casadevall, A.,Casadevall,E.
, p. 4921 - 4928 (1984)
ks/kc ratios, representative of nucleophilic solvent assistance were obtained for solvolyses of hindered secondary substrates.Reactions products were also investigated.Failure to observe a rate-product correlation underlines the noni
The mechanism of solvolysis of 2-adamantyl azoxytosylate: Isotopic labelling, medium effect, and attempted deoxygenation studies
Conner, John K.,Haider, Johanna,Hill, M.N. Stuart,Maskill, Howard,Pestman, Monique
, p. 862 - 868 (1998)
Rates of solvolysis of 2-adamantyl azoxytosylate (1) have been measured over a range of temperatures in ethanoic acid, methanoic acid, 50:50 (v/v) trifluoroethanol:water, 80:20 (v/v) trifluoroethanol:water, 97:3 (w/w) trifluororoethanol:water, and 70:30 (v/v) ethanol:water. For comparison, rates of solvolysis of 2-adamantyl tosylate (2) have also been measured in 50:50, 80:20, and 90:10 (v/v) trifluoroethanol:water, and for both compounds, activation parameters have been determined. These and results published earlier allow a correlation of the two reactions and indicate that the m value for 2-adamantyl azoxytosylate solvolysis is only 0.46. This is one of the lowest m values for a reaction that is unambiguously an S(N)1 solvolysis. We have also recorded the 17O NMR spectrum of the 2-adamantyl tosylate formed from 17O-labelled 2-adamantyl azoxytosylate in deuteriochloroform, and the millimeter-wave spectrum of the nitrous oxide evolved in the hydrolysis of 18O-labelled 2-adamantyl azoxytosylate. These labelling studies have provided more detailed knowledge of the S(N)l fragmentation mechanism of 1 and exclude a mechanism of reaction via rearrangement to N- nitroso,N-(2-adamantyl),O-(p-toluenesulfonyl)hydroxylamine (5). Attempted deoxygenation of 1 to give 2-adamantyl diazotosylate (8) and a subsequent fragmentation proved unsuccessful.
A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
supporting information, p. 2692 - 2698 (2013/01/15)
Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener. Georg Thieme Verlag KG Stuttgart · New York.
Hyperconjugative control by remote substituents of diastereoselectivity in the oxygenation of hydrocarbons
Gonzalez-Nunez, Maria E.,Royo, Jorge,Castellano, Gloria,Andreu, Cecilia,Boix, Carmen,Mello, Rossella,Asensio, Gregorio
, p. 831 - 834 (2007/10/03)
(figure presented) The oxidation of 2-substituted adamantanes (2) with TFDO (1) is reported. The data show a stereodifferentiation of the chemical environments induced by remote electron-withdrawing substituents which produces remarkable Z/E diastereosele
