2040-02-0Relevant articles and documents
Investigations of the generality of quaternary ammonium salts as alkylating agents in direct C-H alkylation reactions: Solid alternatives for gaseous olefins
Sch?nbauer, David,Spettel, Manuel,Pollice, Robert,Pittenauer, Ernst,Schnürch, Michael
supporting information, p. 4024 - 4030 (2019/04/29)
C-H alkylation reactions using short chain olefins as alkylating agents could be operationally simplified on the lab scale by using quaternary ammonium salts as precursors for these gaseous reagents: Hofmann elimination delivers in situ the desired alkenes with the advantage that the alkene concentration in the liquid phase is high. In case a catalytic system did not tolerate the conditions for Hofmann elimination, a very simple spatial separation of both reactions, Hofmann elimination and direct alkylation, was achieved to circumvent possible side reactions or catalyst deactivation. Additionally, the truly catalytically active species of a rhodium(i) mediated alkylation reaction could be identified by using this approach.
Quaternary Ammonium Salts as Alkylating Reagents in C-H Activation Chemistry
Spettel, Manuel,Pollice, Robert,Schnürch, Michael
, p. 4287 - 4290 (2017/08/23)
A rhodium(I)-catalyzed alkylation reaction of benzylic amines via C(sp3)-H activation using quaternary ammonium salts as alkyl source is described. The reaction proceeds via in situ formation of an olefin via Hofmann elimination, which is the actual alkylating reagent. This represents an operationally simple method for substituting gaseous and liquid olefins with solid quaternary ammonium salts as alkylating reagents, which is transferable to other C-H activation protocols as well.
Gas-phase and solution basicities of some alkyl 2,6-dialkylphenyl ketones: A comparative analysis
Dell'erba, Carlo,Gruttadauria, Michelangelo,Mugnoli, Angelo,Noto, Renato,Novi, Marino,Occhiucci, Giorgio,Petrillo, Giovanni,Spinelli, Domenico
, p. 4565 - 4573 (2007/10/03)
The gas-phase basicity of a number of alkyl 2,6-dialkylphenyl ketones (2,6-R2C6H3COR') has been found to be almost insensitive to structural variations, as a result of a compensation of steric and electronic effects associated with the bulkiness and to the polarizability, respectively, of R and/or R'. On the contrary, the basicity in concentrated sulfuric acid undergoes, along the same series of compounds, a variation of nearly 8 pK units, as a consequence of steric inhibition of solvation of the protonated carbonyl as the main effect played by R and/or R'. The results in the condensed phase agree very nicely with recent findings relevant to some 4- substituted 2,6-dimethylacetophenones and 4-substituted acetophenones as well as with data for a large number of dialkyl or alkyl aryl ketones (either from the literature or determined herein) leading to an overall pK(BH+) vs. m* correlation (slope = 8.8, n = 31, r = 0.996; Eq. (3)) which appears to be of general significance and identifies steric inhibition of solvation as a common prevailing factor influencing the carbonyl basicity, at least in the absence of strong conjugative interactions. (C) 2000 Elsevier Science Ltd.
Convenient preparation of mononuclear and dinuclear ruthenium hydride complexes for catalytic application
Busch, Stefan,Leitner, Walter
, p. 2305 - 2306 (2007/10/03)
A mixture of commercially available [Ru(cod)(η3-C4H7)2] and PCy3 reacts with H2 to give [RuH2(H2)2(PCy3)2] in high yields, whereas [Ru
Chelation-Controlled, Palladium-Catalyzed Arylation of Enol Ethers with Aryl Triflates. Ligand Control of Selection for α- or β-Arylation of ethene
Larhed, Mats,Andersson, Carl-Magnus,Hallberg, Anders
, p. 285 - 304 (2007/10/02)
Palladium-catalyzed arylation reactions of ethene (1) with a series of aryl triflates were performed under a variety of reaction conditions.In particular, the influence of phosphine ligands and halide additives on regioselectivity were studied.It was found that the chelation-controlled arylation of 1 affords an expedient route for the conversion of phenols into arylacetaldehydes.Alternatively, the same starting materials could be used to synthesize acetophenones by reversing the regioselectivity with bidentate phosphine ligands.
