- Alkyl Grignard cross-coupling of aryl phosphates catalyzed by new, highly active ionic iron(II) complexes containing a phosphine ligand and an imidazolium cation
-
A novel family of ionic iron(ii) complexes of the general formula [HL][Fe(PR′3)X3] (HL = 1,3-bis(2,6-diisopropylphenyl)imidazolium cation, HIPr, R′ = Ph, X = Cl, 2; HL = HIPr, R′ = Cy, X = Cl, 3; HL = HIPr, R′ = Ph, X = Br, 4; HL = HIPr, R′ = Cy, X = Br, 5; HL = 1,3-bis(2,4,6-trimethylphenyl)imidazolium cation, HIMes, R′ = Cy, X = Br, 6) was easily prepared via a stepwise approach in 88%-92% yields. In addition, an ionic iron(ii) complex, [HIPr][Fe(C4H8O)Cl3] (1), has been isolated from the reaction of FeCl2(THF)1.5 with one equiv. of [HIPr]Cl in 90% yield and it can further react with one equiv. of PPh3 or PCy3, affording the corresponding target iron(ii) complex 2 or 3, respectively. All these complexes were characterized by elemental analysis, electrospray ionization mass spectrometry (ESI-MS), 1H NMR spectroscopy and X-ray crystallography. These air-insensitive complexes 2-6 showed high catalytic activities in the cross-coupling of aryl phosphates with primary and secondary alkyl Grignard reagents with a broad substrate scope, wherein [HIPr][Fe(PCy3)Br3] (5) was the most effective. Complex 5 also catalyzes the reductive cross-coupling of aryl phosphates with unactivated alkyl bromides in the presence of magnesium turnings and LiCl, as well as the corresponding one-pot acylation/cross-coupling sequence under mild conditions.
- Li, Zhuang,Liu, Ling,Sun, Hong-Mei,Shen, Qi,Zhang, Yong
-
p. 17739 - 17747
(2016/11/18)
-
- Ionic iron (II) composition as well as preparation method and application thereof
-
The invention discloses an ionic iron (II) composition as well as a preparation method and application thereof. The ionic iron (II) composition contains phosphine ligands and imidazole (quinoline) cations, and the general formula of the ionic iron (II) is [Fe(PR3)X3][(R1NCHnCHnNR1)CH], wherein X is selected from one of chlorine or bromine. The ionic iron (II) composition containing the phosphine ligands and the imidazole (quinoline) cations can efficiently catalyze a phosphoric acid aryl diethyl ester compound and an alkyl group Grignard reagent to perform a crisscross coupling reaction, and particularly can effectively catalyze an unactivated phosphoric acid aryl diethyl ester compound and the alkyl group Grignard reagent to perform the reaction.
- -
-
Paragraph 0057
(2017/01/02)
-
- Iron-catalyzed alkylations of aryl sulfamates and carbamates
-
The alkylation of aryl sulfamates and carbamates using iron catalysis is reported. The method constructs sp2-sp3 carbon-carbon bonds and provides synthetically useful yields across a range of substrates (>35 examples). The directing group ability of sulfamates and carbamates, accompanied by their low reactivity toward conventional cross-couplings, renders these substrates useful for the synthesis of polyfunctionalized arenes.
- Silberstein, Amanda L.,Ramgren, Stephen D.,Garg, Neil K.
-
supporting information; experimental part
p. 3796 - 3799
(2012/08/28)
-
- Unprecedented Negishi coupling at C-Br in the presence of a stannyl group as a convenient approach to pyridinylstannanes and their application in liquid crystal synthesis
-
(Chemical Equation Presented) The 2-bromo-5(or 6)-tri-n- butylstannylpyridines, prepared from dibromopyridines and i-PrMgCl at room temperature, undergo Negishi coupling with either alkyl or arylzinc chlorides. The new alkyl- and aryl-substituted pyridylstannanes produced are shown to be suitable for further functionalization by Stille coupling. A group of new liquid crystalline materials with aromatic cores comprised of pyridine and thiophene rings were prepared utilizing these new pyridinylstannanes as key intermediates.
- Getmanenko, Yulia A.,Twieg, Robert J.
-
p. 830 - 839
(2008/09/18)
-
- Synthesis and antiviral evaluation of 6-(alkyl-heteroaryl)furo[2,3-d] pyrimidin-2(3H)-one nucleosides and analogues with ethynyl, ethenyl, and ethyl spacers at C6 of the furopyrimidine core
-
Sonogashira coupling strategies were employed to synthesize new furo[2,3-d]pyrimidin-2(3H)-one (FuPyrm) 2′-deoxynucleoside analogues. Partial or complete reduction of ethyne-linked compounds afforded ethenyl-and ethyl-linked derivatives. Levels of inhibition of varicella-zoster virus (VZV), human cytomegalovirus (HCMV), a broad range of other DNA and RNA viruses, and several cancer cell lines were evaluated in cell cultures. The anti-VZV potency decreased with increasing rigidity of the side chain at C6 of the FuPyrm ring in the order dec-1-yn-1-yl dec-1-en-1-yl decan-1-yl. In contrast, compounds with a rigid ethynyl spacer between C6 of the FuPyrm ring and a 4-alkylphenyl moiety were more potent inhibitors of VZV than the corresponding derivatives with an ethyl spacer. Replacement of the phenyl moiety in 6-(4-alkylphenyl) derivatives with a pyridine ring (in either regioisomeric orientation) gave analogues with increased solubility in methanol but reduced anti-VZV potency, and replacement with a pyrimidine ring reduced the anti-VZV activity even further. The pyridine-ring-containing analogues were ~20-fold more potent inhibitors of VZV than acyclovir but were ~6-fold less potent than BVDU and ~60-fold weaker than the most active 6-(4-pentylphenyl)- substituted prototype.
- Robins, Morris J.,Nowak, Ireneusz,Rajwanshi, Vivek K.,Miranda, Karl,Cannon, John F.,Peterson, Matt A.,Andrei, Graciela,Snoeck, Robert,De Clercq, Erik,Balzarini, Jan
-
p. 3897 - 3905
(2008/02/10)
-
- Preparation of 5-brominated and 5,5′-dibrominated 2,2′-bipyridines and 2,2′-bipyrimidines
-
Efficient syntheses of 5-brominated and 5,5′-dibrominated 2,2′-bipyridines and 2,2′-bipyrimidines, useful for the preparation of metal-complexing molecular rods, have been developed. 5-Bromo-2,2-bipyridine, 5-bromo-5′-n-butyl-2,2′-bipyridine, and 5-bromo-5′-n-hexyl-2,2′-bipyridine were obtained by Stille coupling of 2,5-dibromopyridine with 2-trimethylstannylpyridine or the requisite 5-alkyl-2-trimethylstannylpyridine, obtained via regioselective zincation of a 3-alkylpyridine. BF3 complex in the less hindered of the two reactive positions with lithium di-tert-butyl-(2,2,6,6-tetramethyl-piperidino)zincate. 5,5′-Dibromo-2,2′-bipyridine was obtained by the reductive symmetric coupling of 2,5-dibromopyridine with hexa-n-butyldistannane. The yields of these coupling reactions ranged from 70 to 90%. 5-Bromo- and 5,5′-dibromo-2,2′-bipyrimidines were obtained in yields of 30 and 15%, respectively, by bromination of 2,2′-bipyrimidine, prepared from 2-chloropyrimidine in 80% yield by an improved reductive symmetric coupling procedure.
- Schwab, Peter F.H.,Fleischer, Frank,Michl, Josef
-
p. 443 - 449
(2007/10/03)
-
- New Synthesis of 3-Alkylpyridines
-
An effective method is reported for preparation of 3-alkylpyridines from piperidine and C1-C10 aliphatic alcohols at 300-500 deg C in the presence of a dehydrogenating catalyst.
- Tereshko, A. B.,Tarasevich, V. A.,Kozlov, N. G.
-
p. 258 - 259
(2007/10/03)
-