30222-34-5Relevant academic research and scientific papers
Nickel-Catalyzed Asymmetric Reductive Diarylation of Vinylarenes
Anthony, David,Lin, Qiao,Baudet, Judith,Diao, Tianning
supporting information, p. 3198 - 3202 (2019/02/19)
A nickel-catalyzed asymmetric diarylation reaction of vinylarenes enables the preparation of chiral α,α,β-triarylated ethane scaffolds, which exist in a number of biologically active molecules. The use of reducing conditions with aryl bromides as coupling partners obviates the need for stoichiometric organometallic reagents and tolerates a broad range of functional groups. The application of an N-oxyl radical as a ligand to a nickel catalyst represents a novel approach to facilitate nickel-catalyzed cross-coupling reactions.
Alternatives to Phosphinooxazoline (t-BuPHOX) Ligands in the Metal-Catalyzed Hydrogenation of Minimally Functionalized Olefins and Cyclic β-Enamides
Biosca, Maria,Magre, Marc,Coll, Mercè,Pàmies, Oscar,Diéguez, Montserrat
, p. 2801 - 2814 (2017/08/23)
This study presents a new series of readily accessible iridium- and rhodium-phosphite/oxazoline catalytic systems that can efficiently hydrogenate, for the first time, both minimally functionalized olefins and functionalized olefins (62 examples in total) in high enantioselectivities (ees up to >99%) and conversions. The phosphite-oxazoline ligands, which are readily available in only two synthetic steps, are derived from previous privileged 4-alkyl-2-[2-(diphenylphosphino)phenyl]-2-oxazoline (PHOX) ligands by replacing the phosphine moiety by a biaryl phosphite group and/or the introduction of a methylene spacer between the oxazoline and the phenyl ring. The modular design of the ligands has given us the opportunity not only to overcome the limitations of the iridium-PHOX catalytic systems in the hydrogenation of minimally functionalized Z-olefins and 1,1-disubstituted olefins, but also to expand their use to unfunctionalized olefins containing other challenging scaffolds (e.g., exocyclic benzofused and triaryl-substituted olefins) and also to olefins with poorly coordinative groups (e.g., α,β-unsaturated lactams, lactones, alkenylboronic esters, etc.) with enantioselectivities typically >95% ee. Moreover, both enantiomers of the hydrogenation product could be obtained by simply changing the configuration of the biaryl phosphite moiety. Remarkably, the new catalytic systems also provided excellent enantioselectivities (up to 99% ee) in the asymmetric hydrogenation of another challenging class of olefins – the functionalized cyclic β-enamides. Again, both enantiomers of the reduced amides could be obtained by changing the metal from Ir to Rh. We also demonstrated that environmentally friendly propylene carbonate can be used with no loss of enantioselectivity. Another advantage of the new ligands over the PHOX ligands is that the best ligands are derived from the affordable (S)-phenylglycinol rather than from the expensive (S)-tert-leucinol. (Figure presented.).
Mild and regioselective benzylic C-H functionalization: Ni-catalyzed reductive arylation of remote and proximal olefins
He, Yuli,Cai, Yalei,Zhu, Shaolin
supporting information, p. 1061 - 1064 (2017/05/15)
The synergistic combination of NiH-catalyzed alkene isomerization with nickel-catalyzed cross-coupling has yielded a general protocol for the synthesis of a wide range of structurally diverse 1,1-diarylalkanes in excellent yields and high regioselectivities from readily accessible olefin starting materials. Furthermore, the practicality and synthetic flexibility of this approach is highlighted by the successful employment of isomeric mixtures of olefins for regioconvergent arylation.
Palladium-mediated synthesis of 1,1,2-triarylethanes. Application to the synthesis of CDP-840
Lin, Yi-Shan,Kuo, Yi-Chun,Kuei, Chun-Hsiung,Chang, Meng-Yang
, p. 1275 - 1282 (2017/02/10)
A three-step protocol toward 1,1,2-triarylethanes 1 starting with β-ketosulfones 2 is developed. A facile process is carried out for the (1) reduction of 2 with NaBH4, (2) BF3·OEt2-mediated Friedel-Crafts reactions of the
Iridium-catalyzed asymmetric hydrogenation yielding chiral diarylmethines with weakly coordinating or noncoordinating substituents
Tolstoy, Paeivi,Engman, Mattias,Paptchikhine, Alexander,Bergquist, Jonas,Church, Tamara L.,Leung, Abby W.-M.,Andersson, Pher G.
supporting information; experimental part, p. 8855 - 8860 (2009/12/04)
Diarylmethine-containing stereocenters are present in pharmaceuticals and natural products, making the synthetic methods that form these chiral centers are important in industry. We have applied iridium complexes with novel N,P-chelating ligands to the asymmetric hydrogenation of trisubstituted olefins, forming diarylmethine chiral centers in high conversions and excellent enantioselectivities (up to 99% ee) for a broad range of substrates. Our results support the hypothesis that steric hindrance in one specific area of the catalyst is playing a key role in stereoselection, as the hydrogenation of substrates differing little at the prochiral carbon occurred with high enantioselectivity. As a result, excellent stereodiscrimination was obtained even when the prochiral carbon bore, for example, phenyl and p-tolyl groups.
Highly efficient iodine-catalyzed hydroarylation of arenes with styrenes
Chu, Cheng-Ming,Huang, Wan-Ju,Liu, Ju-Tsung,Yao, Ching-Fa
, p. 6881 - 6885 (2008/02/12)
Iodine mediates the hydroarylation of styrenes with arenes and heteroarenes to afford 1,1-diarylalkanes in good to high yields. Details regarding the substrate scope and selectivity of this hydroarylation reaction are discussed.
Synthesis and Reactions of Sulfenic Trifluoromethanesulfonic Anhydrides
Effenberger, Franz,Russ, Werner
, p. 3719 - 3736 (2007/10/02)
Sulfenyl halogenides 1 and 4 react with silver trifluoromethanesulfonate (2) to give aryl 3 and alkylsulfenic trifluoromethanesulfonic anhydrides 5, resp., in good yields; 3 and 5 could not be isolated because of their instability. 1H NMR spectroscopic data of 5a, b, each in dichloromethane and nitromethane, resp., are indicative of a dissoziation to adducts of alkylsulfenylium ions and the solvent.Whereas 3 do not react with aromatic compounds, addition products with diphenylacetylene, arylsulfenylvinyl trifluoromethanesulfonates 11, are formed smoothly, which under the reaction conditions immediately cyclize to give benzothiophenes 10 in excellent yields.
