- Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C?O Bond Activation
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The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3). The strategy relies on PMe3-promoted oxidative addition and transmetalation, and CCl3CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.
- Hu, Wei-Qiang,Pan, Shen,Qing, Feng-Ling,Vicic, David A.,Xu, Xiu-Hua
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supporting information
p. 16076 - 16082
(2020/07/04)
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- A synthetic double (bicyclic hexyl phosphine ) alkane method of the
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The invention discloses a method for synthesizing bis(dicyclohexylphosphine)alkane, belonging to the field of organic synthesis. The method comprises the following steps: (1) under water-free oxygen-free conditions, carrying out amino protection on the initial raw material dicyclohexyl chlorophosphine to obtain dicyclohexyl diethylamino phosphine; and (2) reacting the dicyclohexyl diethylamino phosphine with diethyl cadmium to obtain an di(dicyclohexylphosphine)cadmium intermediate, and reacting with dichloroalkane to synthesize the bis(dicyclohexylphosphine)alkane compound. The method has the advantages of mild reaction conditions and high yield, is easy to operate, lowers the production cost, and is easier for industrial production.
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Paragraph 0006; 0016-0017
(2017/04/03)
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- ETHYLENE TETRAMERIZATION CATALYST SYSTEMS AND METHOD FOR PREPARING 1-OCTENE USING THE SAME
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Disclosed herein is a method of preparing 1-octene at high activity and high selectivity while stably maintaining reaction activity by tetramerizing ethylene using a chromium-based catalyst system comprising a transition metal or a transition metal precursor, a cocatalyst, and a P—C—C—P backbone structure ligand represented by (R1)(R2)P—(R5)CHCH(R6)—P(R3)(R4).
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Page/Page column 12
(2010/06/16)
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- Synthesis of 1,2-bis[(diorgano)phosphino]ethanes via Michaelis-Arbuzov type rearrangements
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A three-step process for the synthesis of the bis(diorganophosphino)ethanes R2PCH2CH2PR2 where R = Et, Ph, iPr, Cy and tBu was examined. In the first step, diorganochlorophosphines were allowed to react with ethylene glycol in the presence of triethylamine at room temperature in THF solution. For R = Ph, iPr and Cy, the bisphosphinites R2POCH2CH2OPR2 were obtained in high yield. For R = Et, the bisphosphinite could not be isolated but may be formed in 80% mixtures with tetraethyldiphosphine, Et2PPEt2, as a minor component. The reaction of di-t-butylchlorophosphine with ethylene glycol occurs at temperatures greater than 130 °C giving di-t-butyl phosphine oxide, tBu2PH(O), as the only phosphorus-containing product. Thermolysis of the bisphosphinites R2POCH2CH2OPR2 (R = Ph, iPr and Cy) at 190-260 °C for 24 h gave the bisphosphine oxides, R2P(O)CH2CH2(O)PR2 in 9% (Ph), 90% (iPr) and 93% (Cy) yields. A DSC study of the thermal rearrangement of Cy2POCH2CH2OPCy2 to Cy2P(O)CH2CH2(O)PCy2 yielded an enthalpy of isomerization of -40.4 ± 0.6 kcal mol-1. Reduction of the bisphosphine oxides, R2P(O)CH2CH2(O)PR2 (R = Ph, iPr and Cy) with trichlorosilane gave the bisphosphines, R2PCH2CH2PR2 in 80-85% yield. The overall yields of the bisphosphines R2PCH2CH2PR2 (R = iPr and Cy) in the three-step process were 61 and 75%, respectively, suggesting that this process should be an attractive synthetic pathway to these two bisphosphines.
- Baldwin, Lawrence C,Fink, Mark J
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p. 230 - 238
(2007/10/03)
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- Process for the preparation of substituted aromatic compounds
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A process for the preparation of a substituted aromatic compound in which a chloroaromatic compound and an alkyl-, alkenyl- or aryl-boronic acid ester or anhydride are coupled in the presence of palladium and a lipophilic aliphatic phosphine comprising at least one branched aliphatic group or a lipophilic aliphatic Dis(phosphine). Preferred phosphines include triisopropyl, triisobutyl and tricyclohexylphosphine.
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