93870-58-7Relevant academic research and scientific papers
Pd(II) complexes of monodentate deoxycholic acid derived binaphthyl diamido phosphites as chiral catalysts in the asymmetric Suzuki-Miyaura cross-coupling
Iannucci, Grazia,Passarelli, Vincenzo,Passera, Alessandro,Iuliano, Anna
, p. 1618 - 1625 (2017)
Chiral binaphthyl diamidophosphites derived from deoxycholic acid were synthesized and used as ligands for the preparation of mononuclear Pd(II) complexes, which were employed as catalysts in the asymmetric Suzuki-Miyaura cross-coupling of arylboronic acids with aryl bromides. Among the different reaction parameters, the substrate concentration emerged as being crucial for the outcome of the reaction: the reaction was faster in a concentrated reaction mixture, and could be performed at 0 °C, where the reaction promoted by the Pd-complexes was more enantioselective affording cross-coupling products with ee up to 70%.
Evaluation of the Transferability of the “Flexible Steric Bulk” Concept from N-Heterocyclic Carbenes to Planar-Chiral Phosphinoferrocenes and their Electronic Modification
Korb, Marcus,Schaarschmidt, Dieter,Grumbt, Martin,K?nig, Matthias,Lang, Heinrich
supporting information, p. 2968 - 2982 (2020/07/02)
The concept of “flexible steric bulk” is discussed at 2-phenylvinyl-1-phosphinoferrocenes. The introduction of freely rotatable 1'-silyl groups increases the catalytic productivity within the synthesis of tri-ortho-substituted biaryls by Suzuki–Miyaura C,C cross-coupling reactions, giving higher yields with 1/4 of catalyst concentration than for the non-silylated derivatives. Electronic modification of the P and the vinyl donor functionalities was investigated by introducing substituents in the para positions of both groups. Therein, electron-withdrawing phosphines increased the yield from 78 to 91 percent for a given biaryl, by changing from a diphenylphosphino to the P(p-CN-C6H4)2 unit. Opposite results, obtained from electron-donating and sterically demanding phosphines, were in accordance with the 1J(31P,77Se) values. However, the electron density of the ferrocenyl backbone, expressed by the redox potential of the first ferrocenyl-related redox process, cannot be correlated with the donor-properties at the P atom. Changing from a PPh2-substituted ferrocene to a (RA)-1,1'-binaphthyl-containing phosphonite, a complex interaction between the axial- and the planar-chiral motifs occurs, resulting a change of the absolute biaryl configuration.
SYNTHESIS OF PHOSPHINE LIGANDS BEARING TUNABLE LINKAGE: METHODS OF THEIR USE IN CATALYSIS
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Page/Page column 16; 17, (2017/12/02)
A series of novel linked indolyl phosphine ligands for transition metals, the synthesis thereof and their use in catalytic coupling reactions are provided. The ligands provide improvements of trasition-metal-catalyzed reactions, including the range of substrates scope, reaction conditions and efficieny.
Palladium-catalyzed annulation of 9-halophenanthrenes with alkynes: Synthesis, structural analysis, and properties of acephenanthrylene-based derivatives
Liu, En-Chih,Chen, Min-Kuan,Li, Jen-Yi,Wu, Yao-Ting
supporting information, p. 4755 - 4761 (2015/03/18)
The palladium-catalyzed annulation of 9-bromoand 9-chlorophenanthrenes with alkynes gave 4,5-disubstituted acephenanthrylenes in yields of 58-95% (9 examples). Asymmetric alkynes, such as 1-phenyl-1-propyne, 1-phenyl-1-hexyne, and 1-cyclopropyl-2-phenylethyne, regioselectively form (cyclo)alkyl-substituted products, following the regular rule that governs the carbopalladation of alkynes. This synthetic protocol can also be utilized in annulations with several p-extended bromoarenes, such as 7-bromo[5]helicene, 5-bromo[4]helicene, 9-bromoanthracene, 3-bromoperylene, and 3-bromofluoranthene, to give the corresponding annulated products in moderate to good yields (51-86%; 6 examples). Similarly, bromocorannulene produced highly curved 1,2-disubstituted cyclopentacorannulenes. Reactions of 6,12-dibromochrysene and 4,7-dibromo[4]helicene with di(4-tolyl) ethyne provided the twofold annulated products in moderate yields. 4,5-Diphenylacephenanthrylene and 6,7-diphenylbenzo[ a]acephenanthrylene thus generated were converted into phenanthro[9,10-e]acephenanthrylene and benzo[ a]phenanthro[9,10-e]acephenanthrylene, respectively, by oxidative cyclodehydrogenation. The structures of 4,5-diphenylacephenanthrylene, 4,5-diphenyldibenzo[a,l]acephenanthrylene, 1,2-diarylcyclopentacorannulenes, and benzo[ a]-phenanthro[9,10-e]acephenanthrylene were verified by X-ray crystallography. The photophysical and electrochemical properties of the selected annulated products were investigated.
Anionic phospho-fries rearrangement at ferrocene: One-pot approach to P,O-substituted ferrocenes
Korb, Marcus,Schaarschmidt, Dieter,Lang, Heinrich
supporting information, p. 2099 - 2108 (2014/05/20)
For the first time the anionic phospho-Fries rearrangement has been successfully applied in ferrocene chemistry, giving access to 1,2-P,O-substituted ferrocenes. The 1,3 (O → C)-migration occurs at ferrocenyl phosphates, thiophosphates, phosphite-borane adducts, and phosphinates by treatment with a base such as lithium diisopropylamide at low temperature, whereas the highest yields were obtained starting from diethylferrocenyl phosphate. Complete reduction of the phosphonate to a primary phosphine and subsequent Stelzer P,C cross coupling allowed the synthesis of Fe(η5-C5H3-2-OMe-PPh2) (η5-C5H5) (1). The qualification of 1 as a supporting ligand in palladium-catalyzed Suzuki-Miyaura C,C couplings has been proven by the synthesis of sterically congested tri-ortho-substituted biaryls under mild reaction conditions in good to excellent yields.
A Planar-Chiral Phosphino(alkenyl)ferrocene for Suzuki-Miyaura C-C Coupling Reactions
Schaarschmidt, Dieter,Grumbt, Martin,Hildebrandt, Alexander,Lang, Heinrich
supporting information, p. 6676 - 6685 (2016/02/19)
Planar-chiral phosphinoferrocene [Fe(η5-C5H3-1-PPh2-2-(E)-CH=CHPh)(η5-C5H5)] (4) was applied in the presence of palladium in Suzuki-Miyaura couplings for the synthesis of sterically congested biaryls. The catalytic activity arises from homogeneous palladium phosphine complexes, of which the potential pre-catalyst [Pd(4)2Cl2] was characterized structurally. The catalytic system is excellently suited for the synthesis of tri-ortho-substituted biaryls under mild conditions (0.1 mol-%, 50-100 C), whereas its application towards the synthesis of tetra-ortho-substituted biaryls is quite limited. Comparing the performance of the reaction with 4 as catalyst and a range of substrates with differing ortho substituents suggests that transmetalation is rate determining. Complex (Sp)-4 was used in atropselective couplings, wherein enantioenrichments of up to 36 % were achieved. The stereoselectivity depends to some extent on the steric properties of the boronic acids; however, slight changes at the aryl halides influence the enantioselectivity.
Highly sterically hindered binaphthalene-based monophosphane ligands: Synthesis and application in stereoselective Suzuki-Miyaura reactions
Meskova, Michaela,Putala, Martin
, p. 894 - 902 (2013/09/23)
A series of new sterically hindered (R)-(2′-aryl-1,1′- binaphthalene-2-yl)phosphanes with ortho-substituted phenyls as aryl groups were prepared via Negishi monoarylation of enantiopure 2,2′-dibromo-1, 1′-binaphthalene followed by lithiation and quenching with diphenylphosphanyl or dicyclohexylphosphanyl chloride. These ligands were applied to the stereoselective Suzuki-Miyaura coupling for the preparation of substituted biaryls. The enantioselectivity correlated positively when increasing the hindrance of the 2′-aryl group of the ligand. Using the best performing diphenylphosphane ligand with a 2,6-dimethoxyphenyl aryl group, various arylnaphthalenes were prepared in high to excellent yields (68-99%) with low to good ee (12-75% ee), the latter being comparable to the best values reported when using other chiral monophosphane ligands.
Planar chiral P,O-compounds derived from ferrocenyl aryl ethers
Schaarschmidt, Dieter,Lang, Heinrich
experimental part, p. 4811 - 4821 (2011/03/01)
The ortho-directed lithiation of FcOC6H4-4-tBu (1) [Fc = (η5-C5H4)(η5-C 5H5)Fe] with nBuLi/tmeda is reported (tmeda = tetramethylethylenediamine). In this reaction, multimetalation occurs to yield novel 1,2-functionalized P,O-derivatives that contain up to four phosphanyl moieties as determined by NMR spectroscopic studies and single-crystal X-ray diffraction analysis. Thus available planar chiral P,O-ferrocenes can successfully be applied in the palladium-catalyzed Suzuki coupling of diverse aryl halides and aryl boronic acids. The aforementioned systems allow the activation of carbon-chlorine bonds in an efficient way and tolerate catalyst loadings as low as 10 ppm. Noteworthy is their remarkable ability to economically generate hindered biaryls under mild reaction conditions. Planar chiral P,O-ferrocenes are excellent ligands in the palladium-mediated C-C coupling of aryl halides and aryl boronic acids. They allow either the conversion ofunreactive substrates or reactions to be performed at low catalyst levels. Moreover, multiply ortho-substituted biaryls are accessible under mild conditions.
Chiral diene as the ligand for the synthesis of axially chiral compounds via palladium-catalyzed suzuki-miyaura coupling reaction
Zhang, Shu-Sheng,Wang, Zhi-Qian,Xu, Ming-Hua,Lin, Guo-Qiang
supporting information; experimental part, p. 5546 - 5549 (2011/03/18)
The first palladium-diene-catalyzed asymmetric Suzuki-Miyaura coupling reaction has been achieved. A number of functionalized biaryls were obtained in high yields and in moderate to high enantioselectivities. The existence of an ortho-formyl group greatly
