17729-74-7Relevant academic research and scientific papers
Electrophilic d0 Cations of Group 4 Metals (M = Ti, Zr, Hf) Derived from Monopentafulvene Complexes: Direct Formation of Tridentate Cp, O, P -Ligands
Fischer, Malte,Schaper, Raoul,Jaugstetter, Maximilian,Schmidtmann, Marc,Beckhaus, Rüdiger
, p. 1192 - 1205 (2018)
The reactions of the monopentafulvene complexes Ti1a and Ti1b with the general formula [CpTi(Cl)(π-η5:σ-η1-C5H4=CR2)] (R = p-tolyl (Ti1a); CR2 = adamantylidene (Ti1b)) with the bidentate P,
Effectiveness and Mechanism of the Ene(amido) Group in Activating Iron for the Catalytic Asymmetric Transfer Hydrogenation of Ketones
Xue, Qingquan,Wu, Rongliang,Wang, Di,Zhu, Meifang,Zuo, Weiwei
, p. 134 - 147 (2021/02/05)
I-interacting ligands of the diphosphino amido-ene(amido) type are effective in activating iron to resemble the properties of precious metals in the catalytic asymmetric transfer hydrogenation of ketones. To further verify the effectiveness of the ene(amido) group, we synthesized four amine(imine) diphosphine iron precatalyst complexes with substituents at α and β positions relative to imino groups (1-3) or with enlarged chelate ring sizes (5,5,6-membered rings) (4). In comparison with the parent trans-(R,R)-[Fe(CO)(Cl)(PPh2CH2CHaNCHPhCHPhNHCH2CH2PPh2)]BF4 (I), the introduction of a methyl group in 1 and 2 reduced the catalytic activity but led to undiminished enantioselectivity as reaction proceeded. In comparison to the iron complexes 1-3 with a 5,5,5-coordination geometry, the complex 4 derived from the new (R,R)-P-NH-NH2 tridentate ligand showed high reactivity comparable to that of I but was unfortunately not enantioselective. The catalytic reactivity of 1, 2, and 4 illustrates the effectiveness of the ene(amido) group. An electronic structure study on the important catalytic intermediate amido-ene(amido) complex 1b proved that iron was activated by an additional I-back-donation-interaction ligand to participate in the traditional metal-ligand bifunctional pathway in the asymmetric transfer hydrogenation reactions.
Synthesis of tertiary phosphine oxides by alkaline hydrolysis of quaternary phosphonium zwitterions using excess t-BuOK and stoichiometric water
Zhong, Chun-Hong,Huang, Wenhua
, p. 1537 - 1546 (2021/01/07)
Hydrolysis of quaternary arylphosphonium zwitterions bearing COO? and those in situ generated from the corresponding salts bearing Ac or OH at the aryl ring by using excess t-BuOK and stoichiometric water affords tertiary arylphosphine oxides in moderate to excellent yield, in contrast to hydrolysis of these zwittertion or salts in aqueous NaOH that mainly provides phosphine oxides with the loss of the aryl group. Under the t-BuOK/water conditions, hydrolysis of carbonyl stabilized ylides Ph3P = CHCOR (R = Ph, Me, and OEt), which partially exist as phosphonium enolates, prefers to produce Ph2P(O)CH2COR. Further reduction of Ph2P(O)CH2COMe by PhSiH3 allows the preparation of Ph2PCH2COMe in 43% yield.
Synthesis of β-Diphenylphosphine-carbonyl Compounds by Reaction of Bromomethyl-carbonyl Compounds with Diphenyl(trimethylsilyl)phosphine
Brunner, Henri,Dylla, Monika E.,Hecht, Gabriele A. M.,Pieronczyk, Willigis
, p. 404 - 406 (2007/10/02)
1-Diphenylphosphinopropan-2-on-hydrobromide (1a), 2-Diphenylphosphino-1-phenylethan-1-on-hydrobromide (2a), and 1,3-Bis(diphenylphosphino)propan-2-on-bis(hydrobromide) (3a) were prepared by the reaction of the corresponding β-bromo-ketones with diphenyl(t
