- One-pot synthesis of binaphthyl-based phosphines via direct modification of BINAP
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Herein reported is the convenient and efficient strategy for the preparation of binaphthyl-based phosphines through direct modification to the commercially available 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) with sodium. In the absence of 15-crown-5-ether, a cyclic sodium dinapthylphospholide intermediate is mainly generated. With 15-crown-5-ether, P-Ph bonds are selectively cleft by Na to produce binaphthyl-based disodium phosphides. The mechanism of selective formation of sodium dinapthylphospholide or binaphthyl-based disodium phosphides is proposed.
- Ye, Jing-Jing,Zhang, Jian-Qiu,Shimada, Shigeru,Han, Li-Biao
-
supporting information
(2021/11/18)
-
- The Trityl-Cation Mediated Phosphine Oxides Reduction
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Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]? as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes. (Figure presented.).
- Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
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supporting information
p. 3035 - 3043
(2021/05/10)
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- Synthesis method of 2, 2 '-bisdiphenylphosphino-1, 1'-binaphthalene
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The invention relates to a synthesis method of 2, 2 '-bisdiphenylphosphino-1, 1'-binaphthalene, which is realized by the following steps: step 1, carrying out BUCHERER reaction on 1, 1 '-binaphthyl-2-naphthol to generate 1, 1'-binaphthyl-2, 2 '-diamine; 2, subjecting 1, 1 '-binaphthyl-2, 2'-diamine to a Sandmeyer reaction to generate binaphthyl dibromide; and 3, carrying out a Grignard reaction onthe binaphthyl dibromide and diphenyl phosphine chloride to generate 2, 2 '-bisdiphenylphosphino-1, 1'-binaphthalene (BINAP). Bulk chemical raw materials are used and are low in price and easy to obtain, and the production cost is effectively reduced; the method has the advantages of easily available raw materials, high reaction yield, simple post-treatment, facilitation of industrial amplification, and strong industrial application prospect.
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- Synthetic method of 2,2'-double diphenyl phosphine-1,1'-dinaphthalene
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The invention discloses a synthetic method of 2,2'-double diphenyl phosphine-1,1'-dinaphthalene. The method comprises the following steps: adding a lithium metal sheet, a ligand, 2,2'-diethoxy-1,1'-dinaphthalene and an ethers solvent are added in a reaction still, heating the materials to the temperature of 60-140 DEG C, reacting the materials for 6-12 hours, dropping chlorodiphenylphosphine at the temperature of 0 DEG C, heating the material to room temperature, and obtaining the product after the reaction is completed; equivalent water quenching is carried out, a product solution is concentrated and filtered, a filter cake is washed with methanol, and vacuum drying is carried out to obtain the product 2,2'-double diphenyl phosphine-1,1'-dinaphthalene (BINAP). The method has the advantages of high yield, low preparation cost, simple post-treatment, high product purity, and is suitable for process enlargement.
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-
Paragraph 0018; 0033; 0034
(2018/10/11)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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- Chemoselective Reduction of Phosphine Oxides by 1,3-Diphenyl-Disiloxane
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Reduction of phosphine oxides to the corresponding phosphines represents the most straightforward method to prepare these valuable reagents. However, existing methods to reduce phosphine oxides suffer from inadequate chemoselectivity due to the strength of the P=O bond and/or poor atom economy. Herein, we report the discovery of the most powerful chemoselective reductant for this transformation to date, 1,3-diphenyl-disiloxane (DPDS). Additive-free DPDS selectively reduces both secondary and tertiary phosphine oxides with retention of configuration even in the presence of aldehyde, nitro, ester, α,β-unsaturated carbonyls, azocarboxylates, and cyano functional groups. Arrhenius analysis indicates that the activation barrier for reduction by DPDS is significantly lower than any previously calculated silane reduction system. Inclusion of a catalytic Br?nsted acid further reduced the activation barrier and led to the first silane-mediated reduction of acyclic phosphine oxides at room temperature.
- Buonomo, Joseph A.,Eiden, Carter G.,Aldrich, Courtney C.
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supporting information
p. 14434 - 14438
(2017/10/23)
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- Highly efficient reduction of tertiary phosphine oxides and sulfides with amine-assisted aluminum hydrides under mild conditions
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Reduction of tertiary phosphine oxides and sulfides into the corresponding phosphines with amine-assisted aluminum hydrides has been studied. The method is characterized by mild conditions, short reaction time, high efficiency, and expanded substrate scope. The new method is an alternative to the currently used methods of reducing phosphine oxides or recycling phosphines engaged in organic reactions.
- Yang, Shuyan,Han, Xinxin,Luo, Minmin,Gao, Jing,Chu, Wenxiang,Ding, Yuqiang
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p. 1156 - 1160
(2015/06/30)
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- Process research on the asymmetric hydrogenation of a benzophenone for developing the manufacturing process of the squalene synthase inhibitor TAK-475
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A practical synthetic method for the synthesis of the chiral benzhydrol 8, which is the key intermediate of the squalene synthase inhibitor TAK-475 (1), has been developed. The method, via asymmetric hydrogenation of the benzophenone 7, employed Noyori's ruthenium precatalyst of the type [RuCl 2(diphosphine)(diamine). We focused on tuning of the chiral diphosphine, and have discovered a novel ligand, DADMP-BINAP (18c), for the catalyst that has allowed reduction of the operating pressure in the asymmetric hydrogenation. The precatalyst containing 18c performed effectively at low hydrogen pressure (1 MPa) with sufficient enantioselectivity, and the result enabled us to successfully obtain enantiomerically pure 8 on a multikilogram scale.
- Goto, Mitsutaka,Konishi, Takahiro,Kawaguchi, Shinji,Yamada, Masatoshi,Nagata, Toshiaki,Yamano, Mitsuhisa
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p. 1178 - 1184
(2011/12/16)
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- BINAP versus BINAP(O) in asymmetric intermolecular Mizoroki-Heck reactions: Substantial effects on selectivities
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2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) was employed as chiral ligand in the enantioselective intermolecular Mizoroki-Heck reaction, whereas the use of cognate BINAP(O) (monooxidized BINAP) is unprecedented. The regio- and enantioselectivity of the arylation of representative cyclic alkenes changes dramatically in the presence of hemilabile BINAP(O) instead of BINAP. The arylation of 2,3-dihydrofuran is perfectly regiodivergent (98:2 versus 0:100) and the arylation of cyclopentene is only enantioselective with BINAP(O) [60 versus 10% enantiomeric excess (ee)]. Use of [Pd2(dba)3]·dba (dba=dibenzylideneacetone) instead of Pd(OAc)2 produces as high as 86% ee in the arylation of cyclopentene.
- Woeste, Thorsten H.,Oestreich, Martin
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supporting information; experimental part
p. 11914 - 11918
(2011/11/29)
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- Improved syntheses of phosphine ligands by direct coupling of diarylbromophosphine with organometallic reagents
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Br versus Cl: It is found that the use of diarylbromophosphines instead of diarylchlorophosphines is crucial for their direct coupling with binaphthylmagnesium bromide or BINOL triflate. This finding has led to an improved preparation of both electron-deficient BINAP-type phosphine ligands and several important Buchwald's ligands. Copyright
- Liu, Lei,Wu, Hai-Chen,Yu, Jin-Quan
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supporting information; experimental part
p. 10828 - 10831
(2011/11/04)
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- A PROCESS FOR THE REDUCTION OF A TERTIARY PHOSPHINE OXIDE TO THE CORRESPONDING TERTIARY PHOSPHINE IN THE PRESENCE OF A CATALYST AND USE OF A TERTIARY PHOSPHINE FOR REDUCING A TERTIARY PHOSPHINE OXIDE IN THE PRESENCE OF A CATALYST
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A process for the conversion of a tertiary phosphine oxide to the corresponding tertiary phosphine comprising reacting said tertiary phosphine oxide with a reducing tertiary phosphine, in the presence of a catalyst that catalyzes the conversion.
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Page/Page column 1
(2011/10/13)
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- Method for Producing Polyhydroxyalkanoates
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The invention relates to a process for preparing polyhydroxyalkanoates by polymerization of lactones of the general formula I, where the substituents and the index n have the meanings given in the description, in the presence of at least one catalyst of the formula (II) LIMaXam, where the substituents and indices have the meanings given in the description. The invention further relates to poly-3-hydroxybutyrates which have a novel property profile and are obtainable for the first time by means of this process, and also biodegradable polyester mixtures based on these poly-3-hydroxybutyrates.
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- Reduction of tertiary phosphine oxides with DIBAL-H
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(Chemical Equation Presented) The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-II) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed.
- Busacca, Carl A.,Raju, Ravinder,Grinberg, Nelu,Haddad, Nizar,James-Jones, Paul,Lee, Heewon,Lorenz, Jon C.,Saha, Anjan,Senanayake, Chris H.
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p. 1524 - 1531
(2008/04/12)
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- Method Of Reducing A Functional Group In An Oxidized Form
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A novel method of reducing a functional group in an oxidised form. The invention relates more particularly to the reduction of aldehyde, ketone, ester, lactone, nitrile or phosphine oxide groups. The reduction method according to the invention is characterised in that it comprises exposing the substrate including the functional group to be reduced to the presence of a siloxane-type compound of the following formula (I), combined with a Lewis acid-type catalyst. In said formula (I):—R1 and R2, which are the same or different, are an alkyl, cycloalkyle or aryl group, —X is a digit from 0 to 50.
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Page/Page column 12
(2008/12/08)
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- A catalytic method for the reduction of secondary and tertiary phosphine oxides
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TMDS has been found to be an efficient hydride source for the reduction of tertiary and secondary phosphine oxides using a catalytic amount of Ti(Oi-Pr)4. All classes of tertiary phosphine oxides, such as triaryl, trialkyl, and diphosphine, were effectively reduced. Georg Thieme Verlag Stuttgart.
- Berthod, Mika?l,Favre-Réguillon, Alain,Mohamad, Jahjah,Mignani, Gérard,Docherty, Gordon,Lemaire, Marc
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p. 1545 - 1548
(2008/02/05)
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- Modification of ligand properties of phosphine ligands for C-C and C-N bond-forming reactions
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A series of ligands have been prepared for use in Pd-catalysed coupling reactions to form C-C and C-N bonds; significant differences are exhibited by similar ligands containing different phosphorus substituents.
- Morris, David J.,Docherty, Gordon,Woodward, Gary,Wills, Martin
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p. 949 - 953
(2008/02/04)
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- PROCESS FOR PREPARATION OF DIPHOSPHINE COMPOUNDS AND INTERMEDIATES FOR THE PROCESS
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A production method of a_compound represented by the formula wherein R1a, R1b, R1c, R1d, R1e, R1f, R2a, R2b, R2c R2d, R2e and R2f are the same or different and each is a hydrogen atom and the like, and R3, R4, R5, R6, R7, R8, R9 and R10 are the same or different and each is a hydrogen atom and the like, or a salt thereof, which comprises reacting a compound represented by the formula wherein X is a leaving group and other symbols are as defined above, or a salt thereof, with a phosphine-borane complex represented by the formula wherein the symbols are as defined above, or a salt thereof, in a solvent in the presence of an amine and a nickel catalyst, is provided.
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- Asymmetric allylic alkylation catalyzed by Pd(II)-complexes with (S)-BINPO, a hemilabile axially chiral P,O-heterodonor inducer
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A complex generated in situ from [Pd(η3-C3H 5)Cl]2 and (S)-BINPO 1 is an active catalyst in the asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl esters 6 via a malonate anion with ee's up to 81% being obtained. Rate and stereoselectivity of the reaction are dramatically influenced by the solvent. The Pd-complex [(S)-(BINPO)Pd(η3-1,3-diphenylallyl)] 5has been synthesized and its structure in the solid state determined by X-ray diffraction. The stoichiometric reaction of 5 with malonate anion affords the alkylated product of the same configuration as the one obtained in the catalytic reaction at room temperature in nearly identical enantiomeric purity (71%).
- Gladiali, Serafino,Taras, Rossana,Ceder, Rosa M.,Rocamora, Merce,Muller, Guillermo,Solans, Xavier,Font-Bardia, Merce
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p. 1477 - 1485
(2007/10/03)
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- Stereospecific deoxygenation of phosphine oxides with retention of configuration using triphenylphosphine or triethyl phosphite as an oxygen acceptor
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(Chemical Equation Presented) A new protocol for deoxygenation of various phosphine oxides with retention of configuration is described. The advantage of the new method includes milder conditions and considerably shortened reaction times. Mechanistic studies about the oxygen transfer between the starting phosphine oxide and the sacrificial triphenylphosphine are also presented.
- Wu, Hai-Chen,Yu, Jin-Quan,Spencer, Jonathan B.
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p. 4675 - 4678
(2007/10/03)
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- Diphosphine mono-sulfides: Readily available chiral monophosphines
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Enantiomerically pure (R)-BINAP, (R)-Tol-BINAP, (R,R)-Me-DUPHOS and (R,R)-DIOP were converted into the corresponding mono-sulfides by treatment with elemental sulfur in benzene.
- Chapman, Christopher J.,Frost, Christopher G.,Gill-Carey, Michael P.,Kociok-Koehn, Gabriele,Mahon, Mary F.,Weller, Andrew S.,Willis, Michael C.
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p. 705 - 710
(2007/10/03)
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- Perfluoro-n-alkylsulfonic acid derivatives
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Described are bis(perfluoro-n-alkane-sulfonate) compounds, methods for preparing these compounds and use of these compounds, for example as starting materials for the synthesis of chiral and phosphine ligands for transition metal catalysts.
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Page column 17
(2010/01/30)
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- Stereospecific reduction of phosphine oxides to phosphines by the use of a methylation reagent and lithium aluminum hydride
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(equation presented) Various phosphine oxides are efficiently reduced by the use of a methylation reagent and lithium aluminum hydride. Optically active P-chirogenic phosphine oxides are also reduced with inversion of configuration at phosphorus atom by treatment with methyl triflate, followed by reaction with LiAlH4.
- Imamoto, Tsuneo,Kikuchi, Shin-Ichi,Miura, Tomoya,Wada, Yoshiyuki
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- Preparation of organohalosilanes
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When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder and a copper catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, a poly(organo)phosphino compound is added to the contact mass. The invention is successful in producing organohalosilanes at a significantly improved production rate without reducing the selectivity of useful silane.
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- Ruthenium-I0D0-optically active phosphine complex
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This invention is concerned with a ruthenium-iodo-optically active bidentate phosphine complex of the formula (I):[Ru-(I)q-(T1)n(SOL)r(L)]m(T2)p(I)s(I)wherein T1 represents a carboxylic acid anion, SOL represents a polar solvent, L represents an optically active bidentate phosphine ligand, T2 represents an anion different from halogen atom anions and carboxylic acid anions, n denotes 0 or 1, r denotes 0, 3 or 4, m denotes 1 or 2, q denotes 0 or 1, or where m is 2, q may represent 1 or 1.5, p denotes 0 or 1, and s denotes 0, 1 or 2 is prepared. Said phosphine complex is usefull as an efficient catalyst for asymmetrically hydrogenating 4-methylene-2-oxetanone into optically active 4-methyl-2-oxetanone.
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- Chelating retardation effect in nickel assisted phosphinatioa: Syntheses of atropisomeric P,N ligands
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Ni(PPh3)2Cl2 was found to be an effective reagent in nickel assisted phosphination of biaryl O,N triflates with chlorodiphenylphosphine to yield atropisomeric P,N ligands. The chelating effect of the substrates in the reaction played an important role. Only the monodentate PPh3 rather than bidentate dppe (1,2-bis(diphenylphosphino)ethane) nickel complex was found to be an effective reagent. (C) 2000 Elsevier Science Ltd.
- Kwong, Fuk Yee,Chan, Albert S.C.,Chan, Kin Shing
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p. 8893 - 8899
(2007/10/03)
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- Process for preparing optically active 1-(p-methoxybenzyl)-1,2,3,4,5,3,7,8-octahydroisoquinoline
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Optically active 1-(p-methoxybenzyl)-1,2,3,4,5,6,7,8-octahydroisoquinoline having the formula (I) is prepared by asymmetric hydrogenation of the corresponding 3,4,5,6,7,8-hexahydro-compound or of the new 1-(p-methoxybenzyl)-3,4,5,6,7,8-hexahydroisoquinoline dihydrogenated phosphate in the present of chiral iridium-phosphine complexes. This product is an intermediate product in the synthesis of cough-relieving dextromethorphanne and analgesic levorphanol. STR1
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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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- Process for producing optically active benzhydrol compounds
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A process for producing a benzhydrol compound (II) which comprises hydrogenating a benzophenone compound (I) in the presence of a hydrogenation catalyst consisting of a transition metal complex, a base and an optically active diamine compound: STR1 wherein R1 to R10 each represents H, OH, C1-4 alkyl, C1-4 alkoxy, C1-4 alkanoyl, etc., R2 and R3, and R8 and R9 may form --CH=CH--CH=CH--, or any two of R1 to R9 adjacent to each other may be bonded to thereby form --OCH2 O-- or --(CH2)3 --. By using this process, optically active benzhydrol compounds which have a high purity and are useful as, for example, intermediates in the synthesis of drugs can be produced by simple procedures.
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- Synthesis and evaluation of a new chiral ligand: 2-diphynlarsino-2'- diphenylphosphino-1,1'-binaphthyl (BINAPAs)
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Chiral 2-diphenylarsino-2'-diphenylphosphino-1,1'-binaphthyl (BINAPAs) was synthesized and found to be an effective ligand in an aryl triflate- using asymmetric Heck reaction.
- Cho, Suk Young,Shibasaki, Masakatsu
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p. 1773 - 1776
(2007/10/03)
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- 'Methyldiopium' and 'methylbinapium', chiral phosphonium-phosphine ligands
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Monomethylphosphoniums derived from (R,R)-diop ('methyldiopium' 2·I) and (R)-binap ('methylbinapium' 7·I) are described. The crystal structure of 7·I is given, and 2·I is shown to act as a ligand of carbonyliron.
- Leglaye, Pascale,Donnadieu, Bruno,Brunet, Jean-Jacques,Chauvin, Remi
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p. 9179 - 9182
(2007/10/03)
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- N-substituted-7-amino-5-hydroxy-3-oxoheptanoic acid derivatives and method for producing the same
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Compounds represented by the following general structural formula (1) and methods for producing the compounds: STR1 R1 represents a group such as benzyloxycarbonyl, R2 represents a lower alkyl group, R3 represents a hydrogen atom or a protecting group, each of M1 and M2 represents a metal atom, and n represents the atomic valence of M1. Intermediates for HMG-CoA reductase inhibitors can be prepared safely and easily from these compounds.
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- Convenient and direct preparation of tertiary phosphines via nickel-catalysed cross-coupling
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Nickel-catalysed cross-coupling of aryl sulfonates and aryl halides with chlorodiphenylphosphine and a reductant directly affords tertiary phosphines, which have application in a wide variety of asymmetric catalysis.
- Ager, David J.,East, Michael B.,Eisenstadt, Amihai,Laneman, Scott A.
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p. 2359 - 2360
(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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- Process for preparing optically active 4-methyl-2-oxetanone
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A process for preparing optically active 4-methyl-2-oxetanone which comprises asymmetrically hydrogenating 4-methylene-2-oxetanone in the presence of a ruthenium-optically active phosphine complex. Optically active 4-methyl-2-oxetanone can easily and economically be obtained at high optical purity.
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- Process for preparing optically active 4-methyl-2-oxetanone
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A process for preparing optically active 4-methyl-2-oxetanone which comprises asymmetrically hydrogenating 4-methylene-2-oxetanone in the presence of a ruthenium-optically active phosphine complex. Optically active 4-methyl-2-oxetanone can easily and economically be obtained at high optical purity.
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- Asymmetric hydrogenation of aromatic-substituted olefins using cationic ruthenium(III) complexes
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A process for the asymmetric reduction of carboxylic acids of the formula STR1 or the amine salts thereof, where R and R1 are the same or different and are hydrogen, alkyl, cycloalkyl or haloalkyl and Ar is aryl or substituted aryl is disclosed.
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-
- Practical Synthesis of (R)- or (S)-2,2'-Bis(diarylphosphino)-1,1'-binaphthyls (BINAPs)
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Practical methods for the synthesis of (R)- or (S)-2,2'bis(diarylphosphino)-1,1'-binaphthyls (BINAPs), useful ligands for transition-metal-catalyzed asymmetric reactions, have been developed. (+/-)-2,2'-Bis(diphenylphosphinyl)1,1'-binaphthyl , prepared from 2,2'-dibromo-1,1'-binaphthyl and diphenylphosphinyl chloride, can be resolved into optical antipodes by the use of camphorsulfonic acid or 2,3-di-O-benzoyltartaric acid.Reduction of resolved BINAPO with trichlorosilane in the presence of triethylamine affords optically pure 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP).In a similar manner, several BINAP analogues have been prepared in optically pure form.The present procedures are suitable for obtaining these axially dissymmetric diphosphines in a large scale.The molecular structure of the 1:1:1 complex of (S)-(-)-BINAPO, (1R)-(-)-camphorsulfonic acid, and acetic acid has been studied by single-crystal X-ray analysis.
- Takaya, Hidemasa,Mashima, Kazushi,Koyano, Kinko
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p. 629 - 635
(2007/10/02)
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- Preparation and lithiation of optically active 2,2'-dihalo-1,1'-binaphthyls. A general strategy for obtaining chiral, bidentate ligands for use in asymmetric synthesis
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Chiral, bidentate ligands based on the 1,1'-binaphthyl system have achieved remarkable success in certain asymmetric syntheses that have been reported in the literature. Enantiomeric excesses are often above 90% and may approach 99% or better. In the present paper, it is demonstrated that 2,2'-dibromo-1,1'-binaphthyl and the corresponding diodide can be obtained in preparative quantities with optical purities in excess of 98%. The compounds can be mono- or dilithiated, and the lithio intermediates are configurationally stable from -131°C up to at least -44°C. Yields of the dilithio intermediate are 95% or higher, and the monolithio intermediates can be formed in chemical yields of 80-85%. The discovery provides an efficient, general route for obtaining symmetrical and unsymmetrical chiral, bidentate ligands based on the binaphthyl system. These derivatives are expected to have broad applications in mechanistic studies of asymmetric reactions and in practical synthetic procedures. For example, (R)- and (S)-BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), which are reported to give enantiomeric excesses approaching 100% in certain rhodium-catalyzed hydrogenations, have been synthesized from 2-naphthol in overall yields ranging from 16% to 34%.
- Brown,Berry,Waterman,et al.
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p. 4717 - 4723
(2007/10/02)
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- 2,2'-BIS(DIPHENYLPHOSPHINO)-1,1'-BINAPHTHYL (BINAP). A NEW ATROPISOMERIC BIS(TRIARYL)PHOSPHINE. SYNTHESIS AND ITS USE IN THE Rh(I)-CATALYZED ASYMMETRIC HYDROGENATION OF α-(ACYLAMINO)ACRYLIC ACIDS
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Racemic 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl has been synthesized from 2,2'-dihydroxy-1,1'-binaphthyl in two steps and resolved into optically pure (R)-(+) and (S)-(-) enantiomers by the use of (+)-di-μ-chlorobis dipalladium.This new axially dissymmetric bis(triaryl)phosphine serves as an excellent ligand for Rh(I)-catalyzed asymmetric hydrogenations of α-(acylamino)acrylic acids or esters.Factors controlling the enantioselectivity and mechanistic aspects are discussed on the basis of the 31P-NMR measurements.
- Miyashita, A.,Takaya, H.,Souchi, T.,Noyori, R.
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p. 1245 - 1253
(2007/10/02)
-
