- Asymmetric C-C bond-formation reaction with Pd: How to favor heterogeneous or homogeneous catalysis?
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The enantioselective allylic alkylation of (E)-1,3-diphenylallyl acetate was studied to clarify the heterogeneous or homogeneous character of the Pd/Al2O3-(R)-BINAP catalyst system. A combined approach was applied: the catalytic test
- Reimann, Sven,Grunwaldt, Jan-Dierk,Mallat, Tamas,Baiker, Alfons
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body text
p. 9658 - 9668
(2010/10/20)
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- Selective mono reduction of bis-phosphine oxides under mild conditions
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Bis-phosphine oxides can be selectively reduced to bis-phosphine monoxides under exceptionally mild conditions using triflic anhydride and a thiol. The Royal Society of Chemistry.
- Petersson, Maria J.,Loughlin, Wendy A.,Jenkins, Ian D.
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experimental part
p. 4493 - 4494
(2009/05/06)
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- Palladium(II) and palladium(0) complexes of BINAP(O) (2-(diphenylphosphino)-2′-(diphenylphosphinyl)-1,1′-binaphthyl)
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The coordination organopalladium chemistry of 2-(diphenylphosphino)-2′-(diphenylphosphinyl)-1,1′-binaphthyl (BINAP(O)) was found to be totally different from that of other phosphine-phosphine oxide ligands, as well as of BINAP. The reaction of [(MeCN)2PdCl2] with BINAP(O) (1 equiv) afforded [(BINAP(O))PdCl2] (1), in which BINAP(O) is P,O-chelated to Pd in the solid state (X-ray) and in solution (NMR). Treatment of 1 with free BINAP(O) led to the reversible formation of a P,P-bonded nonchelate, [(BINAP(O))2PdCl2] (2), which could not be isolated due to the equilibrium being strongly shifted toward 1. Reduction of 1 with LiBH4 in the presence of BINAP(O) afforded a new zerovalent Pd complex [(BINAP(O))2Pd] (3), in which both BINAP(O) ligands are P-bonded to Pd and one provides η2-arene coordination via the C=C bond adjacent to the phosphinyl group (X-ray). Oxidative addition of PhI to 3 led cleanly to [(BINAP(O))Pd(Ph)I] (4; Ph trans to O; X-ray) which was also prepared by the reaction of [Pd2(dba)3] with BINAPO and PhI. The ultrasound-promoted I/F exchange reaction of [(BINAPO)Pd(Ph)I] with AgF afforded [(BINAP(O))Pd(Ph)F] (5), which was decomposed thermally to produce a mixture of P-F and C-P reductive elimination products.
- Marshall, William J.,Grushin, Vladimir V.
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p. 555 - 562
(2008/10/08)
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- Synthesis of p,p'-heterotopic binaphthyldiphosphanes (BINAPP') devoid of C2 symmetry from 2,2'-binaphthol
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The introduction of two nonequivalent diarylphosphanyl substituents into the 2- and 2'-positions of 1,1'-binaphthalene has been successfully accomplished in four steps from 1,1'-binaphthalene-2,2'-diol (BINOL) through conversion into the ditriflate followed by sequential substitution of triflate groups mediated by palladium or nickel catalysts. The selective monosubstitution of the triflate has been achieved by introducing the first phosphorated substituent in the form of phosphane oxide through a Pd-catalyzed reaction. The otolyl-substituted diphosphane 4c is a chiral inducer that is more efficient than BINAP both in the Rh-catalyzed asymmetric hydrogenation of acetamido acrylic acid derivatives and in the Pd-catalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate (85% ee).
- Gladiali, Serafino,Dore, Antonio,Fabbri, Davide,Medici, Serenella,Pirri, Giovanna,Pulacchini, Sonia
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p. 2861 - 2865
(2007/10/03)
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- Method for making an optically active diphosphine ligand
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The present invention provides a method for making compound (1) by reacting compound (2) with phosphine oxide (3) in the presence of a transition metal/phosphine complex and optionally reducing the reaction product: STR1 where n represents 0 or 1; the double line having a continuous line and a dotted line represents a double bond or a single bond such that the ring having the double line forms a naphthalene ring or an octahydronaphthalene ring with an adjacent benzene ring; Tf represents a trifluoromethanesulfonyl group; and Ar represents a phenyl group, a substituted phenyl group or a naphthyl group. The present invention provides an economical way to produce compound (1) as a ligand of a complex useful as a catalyst for a variety of asymmetric synthesis reactions.
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- 2-diphenylphosphino-2'-diphenylphosphinyl-1,1'-binaphthalene (BINAPO), an axially chiral heterobidentate ligand for enantioselective catalysis
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Racemic 2-diphenylphosphino-2'-diphenylphosphinyl-1,1'-binaphthalene (BINAPO) 5 has been prepared in four steps from 1,1'-binaphthalene-2,2'-diol (BINOL) 1 and has been resolved with the aid of the C,N-cyclopalladated complex with N,N-dimethyl (S)-1-(1-naphthyl)ethylamine 6. P,O-chelate binding to palladium occurs in solution and this is confirmed in the solid state by X-ray analysis. (S)-BINAPO is an immediate precursor of (S)-BINAP and is itself an effective chiral inducer for the Pd-catalyzed asymmetric hydrosilylation of styrene (over 70% e.e.).
- Gladiali, Serafino,Pulacchini, Sonia,Fabbri, Davide,Manassero, Mario,Sansoni, Mirella
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p. 391 - 395
(2007/10/03)
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- Method for producing optically active diphosphine compounds
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The present invention provides a method for producing novel optically active diphosphine compounds ?2,2'-bis(di-substituted phosphino)-1,1'-binaphthyl compounds! having a selectivity (chemoselectivity or enantioselectivity) and catalytic activity different from those of conventional BINAP compounds. In a method of the present invention for producing an optically active diphosphine compound (i.e., 2,2-bis(di-substituted phosphino)-1,1'-binaphthyl), 2,2'-bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl is reacted, in the presence of a transition metal-phosphine complex, with a phosphineoxide compound represented by the following general formula: wherein A represents a phenyl group; a mono- to tri-substituted phenyl group, wherein each substituent in the substituted phenyl group is individually selected from the group consisting of a halogen atom, a lower alkyl group, a lower alkoxy group or a lower halogenated-alkoxy group such that one or more of the substituents may be the same or different; a naphthyl group; a lower-alkyl naphthyl group; or a lower-alkoxy naphthyl group.
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- Generation of Tertiary Phosphine-Coordinated Pd(0) Species from Pd(OAc)2 in the Catalytic Heck Reaction
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Palladium(II) diacetate reacted with water (1 equiv./Pd) and (R)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl ((R)-BINAP) (3 equiv./Pd) in benzene in the presence of Et3N to give the palladium(0) species Pd2 (1 equiv./Pd), (R)-BINAP monoxide (1 equiv./Pd), and Et3N*HOAc (2 equiv./Pd).The progress of reaction strongly affected by the content of water in the reaction solution.The reduction of Pd(OAc)2 in the presence of PPh3 proceeded in a similar process to give Pd(PPh3)4 and OPPh3.
- Ozawa, Fumiyuki,Kubo, Akihiko,Hayashi, Tamio
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p. 2177 - 2180
(2007/10/02)
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