58498-57-0Relevant academic research and scientific papers
The AZARYPHOS family of ligands for ambifunctional catalysis: Syntheses and use in ruthenium-catalyzed anti-markovnikov hydration of terminal alkynes
Hintermann, Lukas,Dang, Tuan Thanh,Labonne, Aurelie.,Kribber, Thomas,Xiao, Li,Naumov, Pance
supporting information; experimental part, p. 7167 - 7179 (2010/02/28)
The family of AZARYPHOS (aza-aryl-phosphane) phosphane ligands, containing a phosphine unit and sterically shielded nitrogen lone pairs in the ligand periphery, is introduced as a tool for developing ambifunctional catalysis by the metal center and nitrogen lone pairs in the ligand sphere. General synthetic strategies have been developed to synthesize over 25 examples of structurally diverse (6-aryl-2pyridyl)phosphanes (ARPYPHOS), (6alkyl-2-pyridyl)phosphanes (ALPY-PHOS), 4,6-disubsituted l,3-diazin-2ylphosphanes or l,3,5-triazin-2- ylphosphanes, quinazolinylphosphanes, quinolinylphosphanes, and others. The scalable syntheses proceed in a few steps. The incorporation of AZARYPHOS ligands (L) into complexes [RuCp(L)2(MeCN)][PF6] (Cp = cyclopentadieny1)gives catalysts for the anti-Markovnikov hydration of terminal alkynes of the highest known activities. Electronic and steric ligand effects modulate the reaction kinetics over a range of two orders of magnitude. These results highlight the importance of using structurally diverse ligand families in the process of developing cooperative ambifunctional catalysis by a metal and its ligand.
The chemistry of new nitrosyltungsten complexes with pyridyl- functionalized phosphane ligands
Baur, Juergen,Jacobsen, Heiko,Burger, Peter,Artus, Georg,Berke, Heinz,Dahlenburg, Lutz
, p. 1411 - 1422 (2007/10/03)
The coordination chemistry of pyridylphosphanes, such as 2(6-tert- butylpyridyl)diphenylphosphane (Ph2P-tert-Bupy) (6) and 2-(6-tert- butylpyridyl)dimethylphosphane (Me2P-tert-Bupy) (7) towards a number of nitrosyltungsten complexes is reported. Displacement of the loosely coordinated MeCN from [W(CH3CN)3(CO)2(NO)][BF4] led to the following cationic compounds incorporating mono- and bidentate coordinated phosphane ligands: cis,cis-[W(CO)2(NO)(Ph2PR)(η2-Ph2PR)][BF4], [R = 2-pyridyl (9a), 2-picolyl (11)], cis,cis-[W(CO)(NO)(η2-Ph2Ppy)2][BF4] (20), trans,trans-[W(CO)(NO)(η2-Ph2Ppy)2][BPh4] (21), fac-[W(CO)2(NO) (Me2P- py)3][BF4] (16), fac-[W(CO)2(NO)(Me2P-tert-Bupy)3][BF4] (18), cis,cis- [W(CO)2(NO)(Me2Ppy)(η2-Me2Ppy)][BF4] (22), and cis,cis- [W(CO)2(CH3CN)(NO)(Me2P-tert-Bupy)2][BF4] (23a). The cationic complex cis,mer-[W(CO)3(NO)(Ph2P-tert-Bupy)2][PF6] (14) has been prepared by nitrosylation of cis/trans-W(CO)4(Ph2P-tert-Bupy)2 (13). Reactions of 9a, 11, 14, 16, and 18 with hydride transfer reagents afforded trans,- trans- HW(CO)2(NO)(Ph2Ppy)2 (10), trans, trans-HW(CO)2(NO)(Ph2Ppic)2 (12), trans, trans-HW(CO)2(NO)(Ph2-tBupy)2 (15), cis/trans- HW(CO)2(NO)(Me2Ppy)2 (17), and cis/trans-HW(CO)2(NO)(Me2P-tert-Bupy)2 (19), respectively. Reactivity experiments with acetic acid, hydroiodic acid, carbon dioxide, and acetylenedicarboxylic acid were performed, and were found to afford trans-W(CO)(NO)(Ph2Ppy)2(η2-CH3CO2) (24), trans, trans- IW(CO)2(NO)(Ph2Ppy)2 (25), trans-W(HCO2)(CO)2(NO)(Ph2Ppy)2 (26), and trans-W{η2-(Z)C(CO2Me)=CH[C(O)OMe]}(CO)(NO)(Ph2Ppic)2 (27), respectively. The influence of the pyridyl substituent in 10 was probed by a comparative H/D exchange experiment in which 10 and the analogous complex HW(CO)2(NO)(PPh3)2 were treated with MeOD. The deuterated complex trans,trans-WD(CO)2(NO)(Ph2Ppy)2 (28) could be isolated. The structures of 9a, 11, 14, and 20 have been determined by single-crystal X-ray diffraction analysis.
Reaction of Ketone Enolates with 2,4-Dichloropyrimidine. A Novel Pyrimidine to Pyridine Interconversion
Bell, Harold M.,Carver, David R.,Hubbard, James S.,Sachdeva, Yesh P.,Wolfe, James F.,Greenwood, Thomas D.
, p. 3442 - 3444 (2007/10/02)
Treatment of 2,4-dichloropyrimidine (1) with a series of ketone potassium enolate in liquid NH3 results in a novel ring transformation leading to the formation of 6-(cyanamino)pyridines (8a-c).An SN(ANRORC) mechanism initiated by nucleophilic addition of the enolate to C6 of 1 is proposed.The pyrimidine-pyridine transformation involves displacement of the N1-C2-N3 portion of pyrimidine with a C-C-N moiety, where the enolate contributes the C-C fragment while NH3 is shown, using 15N-labeled NH3, to be the N donor.
