199342-62-6Relevant articles and documents
Base-Controlled Completely Selective Linear or Branched Rhodium(I)-Catalyzed C?H ortho-Alkylation of Azines without Preactivation
Tran, Ga?l,Hesp, Kevin D.,Mascitti, Vincent,Ellman, Jonathan A.
supporting information, p. 5899 - 5903 (2017/05/12)
A [RhI]/bisphosphine/base catalytic system for the ortho-selective C?H alkylation of azines by acrylates and acrylamides is reported. This catalytic system features an unprecedented complete linear or branched selectivity that is solely dependent on the catalytic base that is used. Complete branched selectivity is even achieved for ethyl methacrylate, which enables the introduction of a quaternary carbon center. Excellent functional group compatibility is demonstrated for both linear and branched alkylations. The operational simplicity and broad scope of this transformation allow for rapid access to functionalized azines of direct pharmaceutical and agrochemical relevance.
C2-Selective Branched Alkylation of Benzimidazoles by Rhodium(I)-Catalyzed C-H Activation
Tran, Ga?l,Confair, Danielle,Hesp, Kevin D.,Mascitti, Vincent,Ellman, Jonathan A.
, p. 9243 - 9252 (2017/09/11)
Herein, we report a Rh(I)/bisphosphine/K3PO4 catalytic system allowing for the first time the selective branched C-H alkylation of benzimidazoles with Michael acceptors. Branched alkylation with N,N-dimethyl acrylamide was successfully applied to the alkylation of a broad range of benzimidazoles incorporating a variety of N-substituents and with both electron-rich and -poor functionality displayed at different sites of the arene. Moreover, the introduction of a quaternary carbon was achieved by alkylation with ethyl methacrylate. The method was also shown to be applicable to the C2-selective branched alkylation of azabenzimidazoles.
Electron-poor olefin polymerization catalysts based on semi-fluorinated bis(phosphane)s
Wursche, Roland,Debaerdemaeker, Tony,Klinga, Martti,Rieger, Bernhard
, p. 2063 - 2070 (2007/10/03)
Two semi-fluorinated bis(phosphane)s, P,P'-(1,2-ethanediyl)-bis[bis(2,4,5-trifluorophenyl)phosphane] (3a), P,P'-(1,2-ethanediyl)bis[bis(2,4-difluorophenyl)phosphane] (3b), and their corresponding Pd(II) and Pt(II)-dichloro complexes (4a,b and 6a,b) have been synthesized. Complexation of P,P'-(1,2-ethanediyl)bis{bis[3,5-di(trifluoromethyl)phenyl]phosphane} (3c) and P,P'-(1,2-ethanediyl)bis[bis(pentafluorophenyl)phosphane] (3d) afforded the related compounds 4c,d and 6c. The Pd(II)-diiodo complexes 5c,d have been obtained from 4c,d by halide exchange with NaI. The solid-state structures of compounds 4b and 5c,d have been determined by single-crystal X-ray diffraction analysis. Activation of 4b-d with MAO produced efficient catalysts for the polymerization of 2-norbornene, which have proved to be superior to the Pd(II)-dichlorides derived from the more electron-rich, structurally related P,P'-(1,2-ethanediyl)bis(diphenylphosphane) (DPPE) or P,P'-(1,3-propanediyl)bis(diphenylphosphane) (DPPP).
Electron withdrawing substituents on equatorial and apical phosphines have opposite effects on the regioselectivity of rhodium catalyzed hydroformylation
Casey, Charles P.,Lin Paulsen, Evelyn,Beuttenmueller, Eckart W.,Proft, Bernd R.,Petrovich, Lori M.,Matter, Brock A.,Powell, Douglas R.
, p. 11817 - 11825 (2007/10/03)
The electronic effects of electron withdrawing aryl substituents on equatorial and apical diphosphines were investigated. Chelating diphosphines designed to coordinate in diequatorial or in apical-equatorial positions were synthesized, and their effects on the regioselectivity of rhodium catalyzed 1-hexene hydroformylation were observed, Only diequatorial coordination was observed for 2,2'-bis[(diphenylphosphino)methyl]-1,1'-biphenyl (BISBI) complexes (BISBI)Ir(CO)2H (8) and [BISBI-(3,5-CF3)]Ir(CO)2H (10), and only apical-equatorial coordination was seen for 1,2-bis(diphenylphosphino)ethane (DIPHOS) complexes (DIPHOS)Ir(CO)2H (14) and [DIPHOS-(3,5-CF3)]Ir(CO)2H (15). For the trans-1,2-bis[(diphenylphosphino)methyl]cyclopropane (T-BDCP) complexes, a mixture of diequatorial and apical-equatorial complexes was seen. For (T-BDCP)Ir(CO)2H (12), 12-ae was favored over 12-ee by 63:37, but for [T-BDCP-(3,5-CF3)]Ir(CO)2H (13) the conformational preference was reversed and a 10:90 ratio of 13-ae:13-ee was seen. The electron withdrawing groups in the equatorial positions of BISBI-(3,5-CF3) (1) and T-BDCP-(3,5-CF3) (2) led to an increase in n-aldehyde regioselectivity in rhodium catalyzed hydroformylation. However, electron withdrawing aryl substituents in the apical positions of DIPHOS-(3,5-CF3) (3) led to a decrease in n-aldehyde regioselectivity in rhodium catalyzed hydroformylation.