- Regiocontrolled Reductive Vinylation of Aliphatic 1,3-Dienes with Vinyl Triflates by Nickel Catalysis
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The regiocontrolled functionalization of 1,3-dienes has become a powerful tool for divergent synthesis, yet it remains a long-standing challenge for aliphatic substrates. Herein, we report a reductive approach for a branch-selective 1,2-hydrovinylation of aliphatic 1,3-dienes with R-X electrophiles, which represents a new selectivity pattern for diene functionalization. Simple butadiene, aromatic 1,3-dienes, and highly conjugated polyene were also tolerated. The combination of Ni(0) and the phosphine-nitrile ligand generally resulted in >20:1 regioselectivity with the retention of the geometry of the C3-C4 double bonds. This reaction proceeds with a broad substrate scope, and it allows for the conjugation of two biologically active units to form more complex polyene molecules, such as tetraene and pentaene as well as heptaene.
- Pang, Xiaobo,Zhao, Zhen-Zhen,Wei, Xiao-Xue,Qi, Liangliang,Xu, Guang-Li,Duan, Jicheng,Liu, Xue-Yuan,Shu, Xing-Zhong
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supporting information
p. 4536 - 4542
(2021/04/07)
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- Asymmetric Synthesis of Chiral Primary Amines by Ruthenium-Catalyzed Direct Reductive Amination of Alkyl Aryl Ketones with Ammonium Salts and Molecular H2
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A ruthenium/C3-TunePhos catalytic system has been identified for highly efficient direct reductive amination of simple ketones. The strategy makes use of ammonium acetate as the amine source and H2 as the reductant and is a user-friendly and operatively simple access to industrially relevant primary amines. Excellent enantiocontrol (>90% ee for most cases) was achieved with a wide range of alkyl aryl ketones. The practicability of this methodology has been highlighted by scalable synthesis of key intermediates of three drug molecules. Moreover, an improved synthetic route to the optimal diphosphine ligand C3-TunePhos is also presented.
- Tan, Xuefeng,Gao, Shuang,Zeng, Weijun,Xin, Shan,Yin, Qin,Zhang, Xumu
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supporting information
p. 2024 - 2027
(2018/02/19)
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- Method for preparing diarylphosphoryl chloride compound
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The invention discloses a method for preparing a diarylphosphochlorine compound and belongs to the field of organic synthesis. The method is as follows: the diarylphosphochlorine compound is preparedby reaction of triarylphosphine as a starting material with phosphorus trichloride in the presence of zinc trifluoromethanesulfonate as a catalyst and distillation. Compared with the prior art, the method has the advantages of high reaction yield and simple post-treatment, is particularly suitable for preparation of the diarylphosphochlorine compound with a substituent, and is more suitable for industrial production. The obtained diarylphosphochlorine compound can be used as a ligand for synthesizing metal catalysts, and is applied to the fields such as organic photoelectric materials and medicines.
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Paragraph 0020-0021
(2018/06/15)
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- A 2,2 the [...] -bis [(3,5- xylyl ) phosphorus] dinaphthalene method for the preparation of
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The invention relates to the field of organic synthesis, and in particular relates to a method for preparing 2, 2'-bis [(3, 5-xylyl) phosphorus) dinaphthalene. The method comprises the following steps: preparing N-methyl piperazine phosphorus dichloride h
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Paragraph 0028; 0039; 0040
(2017/02/28)
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- Diastereoselective desymmetrization of diarylphosphinous acid-borane amides under Birch reduction
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Treatment of diarylphosphinous acid-borane amides possessing chiral amido functionality with an alkali metal solution in liquid ammonia induced a preferential dearomatization of one aryl substituent at phosphorus leading to the formation of non-equimolar amounts of diastereomers. Diastereoselectivity of dearomatization depends strongly on the structure of a chiral auxiliary.
- Stankevi?, Marek
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p. 6082 - 6102
(2015/06/08)
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- Practical synthesis of simplephos ligands: Further development of alkyl-substituted phosphanamines
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Herein we disclose a rapid and easy synthetic procedure to access aryl- and alkyl-substituted phosphanamines (SimplePhos ligands). During the synthesis of a library of diverse aryl-substituted phosphanamine ligands we also found that alkyl-substituted phosphanamines can be synthesized and handled easily. This was unexpected as a previous report described them as highly air-sensitive compounds. Subsequently, we created a library of alkyl-substituted phosphanamines and found some to be highly efficient ligands in copper-catalyzed reactions such as the Cu-catalyzed asymmetric conjugate addition and propargylic alkylation reactions. Moreover, our efforts towards the synthesis of SimplePhos ligands led to the development of an easy and practical synthesis of diaryl(chloro)phosphanes, which is also presented in this paper. Copyright
- Mueller, Daniel,Guenee, Laure,Alexakis, Alexandre
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supporting information
p. 6335 - 6343
(2013/10/21)
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- Palladium-catalyzed allylic alkylation of carboxylic acid derivatives: N-acyloxazolinones as ester enolate equivalents
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Triple A: A general asymmetric allylic alkylation of ester enolate equivalents at the carboxylic acid oxidation state is reported. N-Acylbenzoxazolinone-derived enol carbonates were synthesized and employed in the palladium-catalyzed alkylation reaction. The imide products were readily converted into a series of carboxylic acid derivatives without loss of enantiopurity.
- Trost, Barry M.,Michaelis, David J.,Charpentier, Julie,Xu, Jiayi
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supporting information; experimental part
p. 204 - 208
(2012/02/16)
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- Enantioselective hydrogenation of α-dehydroamino acid esters catalyzed by rhodium complexes with chiral bisaminophosphine ligands
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A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium-catalyzed asymmetric hydrogenations of α-d
- Sun, Xianfeng,Li, Wei,Zhou, Le,Zhang, Xumu
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supporting information; experimental part
p. 1150 - 1154
(2010/06/20)
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- 1,4-BIS-DIPHOSPHINES, 1,4-BIS-DIPHOSPHITES AND 1,4-BIS- DIPHOSPHONITES FROM OPTICALLY ACTIVE (Z)-OLEFINES AS CHIRAL LIGANDS
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Chiral diphosphines, diphosphinites, diphosphites and diphosphonites derived from (Z)-2-butenes suitable to act as chiral ligands, complexes between said diphosphines, diphosphinites, diphosphites and diphosphonites and transition metals, and their utilization as chiral catalysts in stereocontrolled reactions, such as diastereo- and enantioselective reduction reactions, diastereo- and enantioselective hydroformylation reactions, diastereo- and enantioselective hydro cyanation reactions. Process for the preparation of said chiral diphosphines, diphosphinites, diphosphites and diphosphonites and process for the preparation of said complexes and for their utilization in stereocontrolled reactions.
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Page/Page column 21; 23
(2008/06/13)
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- Chiral diphosphorus compounds and their transition metal complexes
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The present invention relates to chiral diphosphorus compounds and their transition metal complexes, to a process for preparing chiral diphosphorus compounds and their transition metal complexes and also to their use in asymmetric syntheses.
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Page/Page column 13-14
(2010/02/11)
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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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- Chiral diphosphorus compounds and transition metal complexes thereof
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Tetrahydrofuran bisphosphines of formula (I), are new. Tetrahydrofuran bisphosphines of formula (I): X1, X2 = bonds or O; R1, R2 = H, 1-20C alkyl, 1-20C fluoroalkyl, 2-20C alkenyl, 4-24C aryl, 5-25C aralkyl, 6-26C aralkenyl, NR7R8, OR8, AOR8, ANR7R8 or OC
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- A new chiral dipyridylphosphine ligand Xyl-P-Phos and its application in the Ru-catalyzed asymmetric hydrogenation of β-ketoesters
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A new chiral dipyridylphosphine ligand Xyl-P-Phos has been synthesized and the structure of (S)-Xyl-P-Phos oxide has been characterized by single crystal X-ray diffraction. The ruthenium complex of this ligand, Ru(R-Xyl-P-Phos)(C6H6)Cl2, has been found to be a highly active, enantioselective and air-stable catalyst for the asymmetric hydrogenation of β-ketoesters and shows good potential for industrial applications.
- Wu, Jing,Chen, Hua,Kwok, Wai Him,Lam, Kim Hung,Zhou, Zhong Yuan,Yeung, Chi Hung,Chan, Albert S.C
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p. 1539 - 1543
(2007/10/03)
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- Carbohydrate Phosphinites as Practical Ligands in Asymmetric Catalysis: Electronic Effects and Dependence of Backbone Chirality in Rh-Catalyzed Asymmetric Hydrogenations. Synthesis of R- or S-Amino Acids Using Natural Sugars as Ligand Precursors
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Vicinal diarylphosphinites derived from carbohydrates are excellent ligands for the Rh(I)-catalyzed enantioselective asymmetric hydrogenation of dehydroamino acid derivatives, producing the highest enantioselectivity of any ligands directly prepared from natural products. The enantioselectivity can be enhanced by the appropriate choice of substituents on the aromatic rings of the phosphinites. For example, the use of phosphinites with electron-donating bis(3,5-dimethylphenyl) groups on phosphorus provides ee's up to 99% for a wide range of amino acids including some with easily removable N-protecting groups. Electron-withdrawing aryl substituents, on the other hand, decrease the enantioselectivity. Sense of chiral induction in the amino acid product depends on the relative juxtaposition of the vicinal diphosphinites on a given sugar backbone. When readily available D-glucopyranosides are used as the starting sugars, 2,3-phosphinites give the S-amino acids and 3,4-phosphinites give the R-amino acids. In the case of aromatic and heteroaromatic amino acids, enantioselectivities > 95% are consistently obtained. Practical considerations such as the ease of ligand synthesis, rates of reactions, catalyst turnover, and scope and limitations in terms of substrates are discussed. A possible explanation for the enhancement of enantioselectivity by electron-rich phosphinites is offered.
- RajanBabu,Ayers, Timothy A.,Halliday, Gary A.,You, Kimberly K.,Calabrese, Joseph C.
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p. 6012 - 6025
(2007/10/03)
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- Selective asymmetric hydrogenation of dehydroamino acid derivatives using rhodium and iridium diphosphinite carbohydrate catalyst compositions
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A process and catalyst composition are provided for the highly efficient enantioselective hydrogenation of dehydroamino acid derivatives. The catalyst composition comprises rhodium or iridium and a diphosphinite carbohydrate ligand, wherein the phosphorous atoms are attached to aromatic groups substituted with electron-donating substituents. Also provided is a means to selectively produce α amino acids in either the L or the D form, based upon use of a sugar in the ligand with phosphinites attached in an absolute Right-Left or Left-Right configuration, respectively.
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- Ligand Electronic Effects in Asymmetric Catalysis: Enhanced Enantioselectivity in the Asymmetric Hydrocyanation of Vinylarenes
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The enantioselectivity of the nickel-catalyzed, asymmetric hydrocyanation of vinylarenes using glucosederived, chiral phosphinite ligands, L, increases dramatically when the ligands contain electron-withdrawing P-aryl substituents.The substrate and solvent also strongly influence the enantioselectivity, with the highest ee's (85-91percent for 6-methoxy-2-vinylnaphthalene (MVN)) obtained for the hydrocyanation of electron-rich vinylarenes in a nonpolar solvent such as hexane.Mechanistic studies suggest the catalytic cycle consists of an initial HCN oxidative addition or vinylarene coordination to "NiL", followed by insertion to form an (η3-benzyl)nickel cyanide complex, and irreversible reductive elimination of the nitrile.A kinetic analysis of the NiLa(COD) (La, P-aryl=3,5-(CF3)2C6H3) catalyzed hydrocyanation of MVN indicates that as the HCN concentration is increased the catalyst resting state shifts from NiLa(COD) to a complex containing both MVN and HCN, presumably the (η3-benzyl)nickel cyanide intermediate NiLa(η3-CH3CHC10H6OCH3)CN.A 31P NMR analysis of the intermediate NiLa(MVN) shows little ground state differentiation of the MVN enantiofaces and suggests that the enantioselectivity is determined later in the mechanism.Deuterium labeling studies suggest that electron-withdrawing P-aryl substituents increase the rate of reductive elimination of the product nitrile from the (η3-benzyl)nickel cyanide intermediate and, on this basis, a rationale for the ligand electronic effect is proposed.
- Casalnuovo, Albert L.,RajanBabu, T. V.,Ayers, Timothy A.,Warren, Timothy H.
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p. 9869 - 9882
(2007/10/02)
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