51440-57-4Relevant articles and documents
Dual-gold(I)-generated trifluoromethylation of terminal alkynes with Togni's reagent
Siah, Huey-San Melanie,Fiksdahl, Anne
supporting information, p. 24 - 33 (2017/03/10)
The interaction of a Au(I) catalyst (JohnPhosAu(I)-MeCN/SbF6) and the Togni's reagent 1, as a source of electrophilic trifluoromethyl group, has been studied in order to develop gold-catalysed alkyne trifluoromethylation reactions. Alkyne-CF3products were prepared in moderate yields (up to 46%) by electrophilic trifluoromethylation of terminal arylalkynes with Togni's reagent 1 in the presence of sub-stoichiometric amounts of gold catalyst (25%). The proposed addition-elimination reaction mechanism proceeds through a Au-Togni Reagent complex with a linear Togni Reagent-O-Au(I)-P-(phosphane) coordination mode (X-ray analysis). Alkyne deprotonation gives rapid formation of protonated Togni Reagent and a σ,π-acetylide dual-Au complex, confirmed by X-ray analysis. It was shown that the σ,π-dual-Au complex activates for trifluoromethylation, most likely by transfer of a [LAu]+fragment to the alkyne substrate. The resulting reactive π-Au+-alkyne intermediate probably undergoes O-/CF3-addition of Togni Reagent, and final elimination of Togni alcohol gives the alkyne-CF3product.
Dynamic kinetic asymmetric [3 + 2] annulation reactions of aminocyclopropanes
De Nanteuil, Florian,Serrano, Eloisa,Perrotta, Daniele,Waser, Jerome
supporting information, p. 6239 - 6242 (2014/05/20)
We report the first example of a dynamic kinetic asymmetric [3 + 2] annulation reaction of aminocyclopropanes with both enol ethers and aldehydes. Using a Cu catalyst and a commercially available bisoxazoline ligand, cyclopentyl- and tetrahydrofurylamines were obtained in 69-99% yield and up to a 98:2 enantiomeric ratio using the same reaction conditions. The method gives access to important enantio-enriched nitrogen building blocks for the synthesis of bioactive compounds.
Alkylenation with Geminal Dialuminoalkane Reagents: The Synthesis of Olefins from Ketones
Piotrowski, Andrzej M.,Malpass, Dennis B.,Boleslawski, Marek P.,Eisch, John J.
, p. 2829 - 2835 (2007/10/02)
Bis(dichloroalumino)methane (BDAM, 1) has been synthesized in high yield from aluminum powder and methylene chloride by a published procedure carefully modified for safety.By the screening away of aluminum metal fine particles and the gradual addition of methylene bromide promoter over the course of reaction, a safe procedure was attained.Although 1 itself was a poor methylenating agent for ketones, its dietherate complex was distinctly more reactive.By exchanging half the halogens of 1 with Me3Al, MeMgBr, or Et3Al, two very effective methylenating agents for ketones, namely CH2(AlClMe)2 (2) and CH2(AlClEt)2 (3), were obtained.As diether ates with Et2O or THF, 2 and 3 smoothly converted a broad variety of ketones (aliphatic, alicyclic, and aromatic) into their corresponding methylene derivatives, with little or no competitive alkylation or reduction.A titanium-modified reagent, Cl2AlCH2TiCl3 (4), was also effective toward ketones, but gave only low conversions of esters to vinyl ethers.Finally, as an example of a multicarbon, alkylenating agent, the reagents 5-7 ((R2Al)2CH(CH2)4CH3, 5, R = Et; 6, R = Cl; and 7, R = Cl or Et) were examined.Good to fair yields of alkylenation were obtained with aromatic ketones, but aliphatic ketones underwent alkylation, hydride reduction, and/or aldol condension.The great influence of alkyl groups and donor solvent on the reactivity of 1-3 is briefly discussed.
