460743-71-9Relevant articles and documents
Tetraethylphosphorodiamidate-Directed Metalation Group: Directed Ortho and Remote Metalation, Cross Coupling, and Remote Phospha Anionic Fries Rearrangement Reactions
Alessi, Manlio,Blackburn, Thomas,Patel, Jignesh J.,Sawinski, Hannah,Snieckus, Victor
, (2020/05/18)
The linked directed ortho and remote metalation (DoM and DreM) and cross-coupling reactions of aryl phosphorodiamidates (Ar-OP(O)(NEt2)2) is reported. The o-iodo and o-boronato aryl tetraethylphosphorodiamidates 3, prepared by DoM, undergo orthogonal Ni- and Pd-catalyzed Suzuki-Miyaura cross coupling to furnish biaryls 4 and 5 in good to excellent yields. Silicon group protection of biaryl 4 via DoM followed by previously unobserved DreM phospha anionic Fries rearrangement affords biaryls 11 which, under acidic conditions, furnish oxaphosphorine oxides 12.
Bis(dialkylphosphino)ferrocene-Ligated Nickel(II) Precatalysts for Suzuki-Miyaura Reactions of Aryl Carbonates
Barth, Emily L.,Davis, Ryan M.,Mohadjer Beromi, Megan,Walden, Andrew G.,Balcells, David,Brudvig, Gary W.,Dardir, Amira H.,Hazari, Nilay,Lant, Hannah M. C.,Mercado, Brandon Q.,Peczak, Ian L.
supporting information, p. 3377 - 3387 (2019/09/30)
Aryl carbonates, a common protecting group in synthetic organic chemistry, are potentially valuable electrophiles in cross-coupling reactions. Here, after performing a thorough evaluation of different precatalysts, we demonstrate that (dcypf)Ni(2-ethylphenyl)(Br) (dcypf = 1,1-bis(dicyclohexylphosphino)ferrocene) is an efficient precatalyst for Suzuki-Miyaura reactions using a variety of aryl carbonates as substrates. Mechanistic studies indicate that (dcypf)Ni(2-ethylphenyl)(Br), which contains a bidentate phosphine that binds in a trans geometry, is an effective precatalyst for these reactions for two reasons: (i) it rapidly forms the Ni(0) active species and (ii) it minimizes comproportionation reactions between the Ni(0) active species and both the unactivated Ni(II) precatalyst and on-cycle Ni(II) complexes to form catalytically inactive Ni(I) species. In contrast, the state of the art precatalyst (dppf)Ni(o-tolyl)(Cl) (dppf = 1,1-bis(diphenylphosphino)ferrocene), which contains a bidentate phosphine that binds in a cis geometry, forms Ni(I) species during activation and is essentially inactive for aryl carbonate couplings. Although the exact reasons on a molecular level why the dcypf system is more active than the dppf system are unclear, our results indicate that in general Ni catalysts supported by the dcypf ligand will give better performance for catalytic reactions involving substrates which undergo relatively slow oxidative addition, such as aryl carbonates.
New, potentially chelating NHC ligands; synthesis, complexation studies, and preliminary catalytic evaluation
Ou, Arnold,Wu, Linglin,Salvador, Alvaro,Sipos, Gellert,Zhao, Guangzhen,Skelton, Brian W.,Sobolev, Alexandre N.,Dorta, Reto
supporting information, p. 3631 - 3641 (2017/03/22)
Two new N-heterocyclic carbene (NHC) ligands bearing 2-morpholino and 2-piperidinyl naphthyl wingtips were synthesised (2-SIMorNap and 2-SIPipNap). Nuclear magnetic resonance studies, in conjunction with crystal structures and derivatisation of the NHC salts using a chiral counteranion, revealed that the ligand wingtips are oriented anti with respect to each other. From the free carbene, palladium, ruthenium and iridium complexes were prepared. NHC-iridium dicarbonyl complexes were made in order to extract the TEP values for these ligands. The study showed that these NHC ligands are more electron-donating than normal, aryl-substituted NHCs. The palladium complexes were tested in representative Suzuki-Miyaura cross-coupling reactions and compared to the state of the art systems. Ruthenium-catalysed ring-closing metathesis with these ligands was also performed. It was found that Grubbs’ 2nd generation catalyst incorporating 2-SIPipNap did not initiate at room temperature and required heating for RCM to occur.