598-53-8Relevant articles and documents
Investigating the α-effect in gas-phase SN2 reactions of microsolvated anions
Thomsen, Ditte L.,Reece, Jennifer N.,Nichols, Charles M.,Hammerum, Steen,Bierbaum, Veronica M.
, p. 15508 - 15514 (2013/11/06)
The α-effect - enhanced reactivity of nucleophiles with a lone-pair adjacent to the attacking center - was recently demonstrated for gas-phase SN2 reactions of HOO-, supporting an intrinsic component of the α-effect. In the present work we explore the gas-phase reactivity of microsolvated nucleophiles in order to investigate in detail how the α-effect is influenced by solvent. We compare the gas-phase reactivity of the microsolvated α-nucleophile HOO-(H2O) to that of microsolvated normal alkoxy nucleophiles, RO-(H2O), in reaction with CH3Cl using a flowing afterglow-selected ion flow tube instrument. The results reveal enhanced reactivity of HOO-(H 2O) and clearly demonstrate the presence of an α-effect for the microsolvated α-nucleophile. The association of the nucleophile with a single water molecule results in a larger Bronsted βnuc value than is the case for the unsolvated nucleophiles. Accordingly, the reactions of the microsolvated nucleophiles proceed through later transition states in which bond formation has progressed further. Calculations show a significant difference in solvent interaction for HOO- relative to the normal nucleophiles at the transition states, indicating that differential solvation may well contribute to the α-effect. The reactions of the microsolvated anions with CH3Cl can lead to formation of either the bare Cl- anion or the Cl-(H2O) cluster. The product distributions show preferential formation of the Cl- anion even though the formation of Cl-(H2O) would be favored thermodynamically. Although the structure of the HOO-(H2O) cluster resembles HO-(HOOH), we demonstrate that HOO- is the active nucleophile when the cluster reacts.
METHOD FOR THE PRODUCTION OF ETHERS
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Page/Page column 8, (2008/06/13)
The invention relates to a method for the production of ethers of formula (I), where R1 and R2 independently = H, substituted or unsubstituted, branched or linear 1 - 20 C alkyl chains, substituted or unsubstituted 5 - 8 C cycloaliphatic groups with a ring size of from 5 - 8 carbon atoms, whereby the ring can be interrupted by a heteroatom, or R1 and/or R2 = unsubstituted or substituted aromatic groups or together form a chain of 5 - 7 methylene groups and R3 = linear or branched 1 - 20 C alkyl chains, by hydrogenation of acetals of formula (II), where R1, R2 and R3 have the meanings given above, in the presence of hydrogen on a catalyst comprising copper oxide, aluminium oxide and optionally, in addition, manganese oxide.
Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents
Hao, Wei,Fujii, Takayoshi,Dong, Tiaoling,Wakai, Youko,Yoshimura, Toshiaki
, p. 193 - 198 (2007/10/03)
Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, ptoluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (la), Pr (1b), and Bu (1d) ? i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield.
