- Stereoselective Synthesis of All Possible Phosferrox Ligand Diastereoisomers Displaying Three Elements of Chirality: Stereochemical Optimization for Asymmetric Catalysis
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All four possible diastereoisomers of phosphinoferrocenyloxazoline (Phosferrox type) ligands containing three elements of chirality were synthesized as single enantiomers. The Sc configured oxazoline moiety (R = Me, i-Pr) was used to control th
- Arthurs, Ross A.,Hughes, David L.,Richards, Christopher J.
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- AlCl3-catalyzed C-H p hosphination of benzene: A mechanistic study
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The characteristics of the reaction for the preparation of dichlorophenylphosphine (DCPP) via benzene and PCl3 in the presence of AlCl3 were studied. Some unique characteristics were observed when a catalytic amount of AlCl3 was used. Namely, more than one mole of DCPP was obtained per mole AlCl3, the reaction solution was layered, and DCPP could be directly separated. Our mechanistic study showed that benzene reacted with PCl3 to form DCPP-AlCl3, and DCPP-AlCl3 dissociated into DCPP and AlCl3, continuing to catalyze this reaction. This resulted in the high catalytic efficiency of AlCl3. The layering of the reaction solution was caused by the immiscibility of DCPP-AlCl3 with the raw materials, greatly facilitating the dissociation process of DCPP-AlCl3. The formation of diphenylphosphorus chloride (DPC) was due to a continuous Friedel-Crafts reaction between DCPP and benzene. DPC cooperated with AlCl3 to form the stable coordination compound DPC-AlCl3 that did not dissociate and was responsible for the deactivation of AlCl3.
- Duan, Haodong,Gao, Jun,Guo, Ge,Han, Yuxi,Leng, Kangwei,Li, Xinjin,Wang, Zhongwei,Xu, Xiaolei,Yu, Qing
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- Synthesis of β-Lactams by Palladium(0)-Catalyzed C(sp3)?H Carbamoylation
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A general and user-friendly synthesis of β-lactams is reported that makes use of Pd0-catalyzed carbamoylation of C(sp3)?H bonds, and operates under stoichiometric carbon monoxide in a two-chamber reactor. This reaction is compatible with a range of primary, secondary and activated tertiary C?H bonds, in contrast to previous methods based on C(sp3)?H activation. In addition, the feasibility of an enantioselective version using a chiral phosphonite ligand is demonstrated. Finally, this method can be employed to synthesize valuable enantiopure free β-lactams and β-amino acids.
- Dailler, David,Rocaboy, Ronan,Baudoin, Olivier
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supporting information
p. 7218 - 7222
(2017/06/13)
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- Base-Induced 1,3-Sigmatropic rearrangement of mesitylphosphonium salts
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Attempted synthesis of the ylide dianion [2,4,6-Me3C 6H2P(CHR)3]2- (2,4,6-Me 3C6H2 = mesityl, R = H or Me) by the reaction of mesitylphosphonium iodides [2,4,6-Me3C6H 2PR3]+I- (R = Me, 1; R = Et, 2) with tBuLi at reflux does not result in the anticipated deprotonation of the phosphorus-bonded R groups. Instead, quantitative 1,3-sigmatropic rearrangement occurs to give new benzylic phosphonium salts [(3,5-Me2C 6H3)CH2PR3]+I - (R = Me, 6; R = Et, 7), in which the phosphonium centre, the R 3P group, is transferred to an ortho-CH3 group. In situ 31P NMR spectroscopic studies show that the reaction is base-activated and stoichiometric with respect to tBuLi. DFT calculations support the conclusion that the rearrangement is thermodynamically favourable in the gas phase and in THF and show that the rearrangement is enthalpically driven. Copyright
- Solomon, Sophia A.,Allen, Lucy K.,Dane, Sarah B. J.,Wright, Dominic S.
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supporting information
p. 1615 - 1619
(2014/04/17)
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- Base-induced 1,3-sigmatropic rearrangement of mesitylphosphonium salts
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Attempted synthesis of the ylide dianion [2,4,6-Me3C6H2P(CHR)3]2- (2,4,6-Me3C6H2 = mesityl, R = H or Me) by the reaction of mesitylphosphonium iodides [2,4,6-Me3C6H2PR3]+I- (R = Me, 1; R = Et, 2) with tBuLi at reflux does not result in the anticipated deprotonation of the phosphorus-bonded R groups. Instead, quantitative 1,3-sigmatropic rearrangement occurs to give new benzylic phosphonium salts [(3,5-Me2C6H3)CH2PR3]+I- (R = Me, 6; R = Et, 7), in which the phosphonium centre, the R3P group, is transferred to an ortho-CH3 group. In situ 31P NMR spectroscopic studies show that the reaction is base-activated and stoichiometric with respect to tBuLi. DFT calculations support the conclusion that the rearrangement is thermodynamically favourable in the gas phase and in THF and show that the rearrangement is enthalpically driven. Teaching an old dog new tricks: First synthesised in 1935, phosphonium salts [2,4,6-Me3C6H2PR3]+I- (2,4,6-Me3C6H2 = mesityl, R = Me or Et) exhibit an unexpected quantitative rearrangement in the presence of tBuLi, in which the phosphine group R3P is transferred to an ortho-CH3 position.
- Solomon, Sophia A.,Allen, Lucy K.,Dane, Sarah B. J.,Wright, Dominic S.
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supporting information
p. 1615 - 1619
(2015/04/27)
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- CHIRAL PHOSPHORUS COMPOUNDS
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The present invention provides P-chiral compounds of general formula (II) and (III): wherein at least one of R21, R25, R26 and R30 is independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; at least one of R22, R24, R27 and R29 are independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R22, R24, R27 and R29 are hydrogen; and R23 and R28 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy; Formula (III): wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.
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Page/Page column 27-28
(2008/12/04)
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- Effect of fluorine and trifluoromethyl substitution on the donor properties and stereodynamical behaviour of triarylphosphines
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A series of 2-, 3- or 4-trifluoromethyl substituted triarylphosphines and their oxide, chalcogenide and Fe(CO)4 derivatives have been prepared and characterised spectroscopically and crystallographically. Electronic effects of CF3 su
- Howell, James A. S.,Fey, Natalie,Lovatt, Jonathan D.,Yates, Paul C.,McArdle, Patrick,Cunningham, Desmond,Sadeh, Einat,Gottlieb, Hugo E.,Goldschmidt, Zeev,Hursthouse, Michael B.,Light, Mark E.
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p. 3015 - 3028
(2007/10/03)
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- Process for the preparation of phenyl- and thienyl-chlorophosphane derivatives
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Organic chlorophosphanes of the formula II STR1 in which R1 =an aromatic or heterocyclic radical and R2 =an aliphatic radical or Cl are prepared by reacting organic phosphorus oxychlorides of the formula I STR2 in which R1 and R2 have the meaning mentioned above with triphenylphosphane (C6 H5)3 P at an elevated temperature. The organic chlorophosphanes II are, in the main, intermediates in various specialized fields, such as the pharmaceuticals, plant protection, dyestuffs and polymers sectors.
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