41692-47-1Relevant articles and documents
Alkoxydiaminophosphine Ligands as Surrogates of NHCs in Copper Catalysis
Pizarro, Juan Diego,Molina, Francisco,Fructos, Manuel R.,Pérez, Pedro J.
supporting information, p. 10330 - 10335 (2020/07/24)
A family of phosphine ligands containing a five-membered ring similar to the popular N-heterocyclic carbene ligands and an alkoxy third substituent has been developed. These alkoxydiaminophosphine ligands (ADAP) can be generated in one pot and reacted with a copper(I) source leading to the high yield isolation of complexes [(ADAP)CuX]2 (X=Cl, Br). The dinuclear nature of these compounds has been established by means of X-ray studies and DOSY experiments. A screening of the catalytic properties of these complexes toward carbene-transfer reactions from diazocompounds to C?H bonds (alkane, arene), olefins or N?H bonds, as well as in CuAAC or nitrene transfer reactions have shown a performance at least similar, if not better, than their (NHC)CuCl analogues, opening a new window in copper catalysis with these readily tunable ADAP ligands.
Functionalization of CnH2n+2 Alkanes: Supercritical Carbon Dioxide Enhances the Reactivity towards Primary Carbon-Hydrogen Bonds
Gava, Riccardo,Olmos, Andrea,Noverges, Bárbara,Varea, Teresa,Funes-Ardoiz, Ignacio,Belderrain, Tomás R.,Caballero, Ana,Maseras, Feliu,Asensio, Gregorio,Pérez, Pedro J.
, p. 3254 - 3260 (2015/10/28)
The functionalization of the primary sites of alkanes is one of the more challenging areas in catalysis. In this context, a novel effect has been discovered that is responsible for an enhancement in the reactivity of the primary C-H bonds of alkanes in a catalytic system. The copper complex Cu(NCMe) (=hydrotris{[3,5-bis(trifluoromethyl)-4-bromo]-pyrazol-1-yl}borate) catalyzes the functionalization of CnH2n+2 with ethyl diazoacetate upon inserting the CHCO2Et unit into C-H bonds. In addition, the selectivity of the reaction toward the primary sites significantly increased relative to that obtained in neat alkane upon using supercritical carbon dioxide as the reaction medium. This was attributed to the effect of the carbon dioxide molecules that withdraw electron density from the fluorine atoms of the ligand, which enhances the electrophilic nature of the metal center. DFT studies validated this proposal.
Silver-catalyzed C-C bond formation between methane and ethyl diazoacetate in supercritical CO2
Caballero, Ana,Despagnet-Ayoub, Emmanuelle,Diaz-Requejo, M. Mar,Diaz-Rodriguez, Alba,Gonzalez-Nunez, Maria Elena,Mello, Rossella,Munoz, Bianca K.,Ojo, Wilfried-Solo,Asensio, Gregorio,Etienne, Michel,Perez, Pedro J.
scheme or table, p. 835 - 838 (2011/12/03)
Even in the context of hydrocarbons' general resistance to selective functionalization, methane's volatility and strong bonds pose a particular challenge. We report here that silver complexes bearing perfluorinated indazolylborate ligands catalyze the reaction of methane (CH4) with ethyl diazoacetate (N2CHCO2Et) to yield ethyl propionate (CH3CH2CO2Et). The use of supercritical carbon dioxide (scCO2) as the solvent is key to the reaction's success. Although the catalyst is only sparingly soluble in CH4/CO2 mixtures, optimized conditions presently result in a 19% yield of ethyl propionate (based on starting quantity of the diazoester) at 40°C over 14 hours.
