755017-61-9Relevant articles and documents
Enantiodivergent Synthesis of Axially Chiral Biphenyls from σ-Symmetric 1,1'-Biphenyl-2,6-diol Derivatives by Single Lipase-Catalyzed Acylative and Hydrolytic Desymmetrization
Kasama, Kengo,Aoyama, Hiroshi,Akai, Shuji
, p. 654 - 661 (2020)
The enzymatic acylative desymmetrization of σ-symmetric 2'-halo-1,1'-biphenyl-2,6-diols was achieved for the first time using commercially available Burkholderia cepacia lipase immobilized on diatomaceous earth to give (S)-mono esters. The hydrolytic desymmetrization of the corresponding diacetates was also achieved using the same lipase to give (R)-mono esters. Our results, therefore, demonstrate that a single lipase can conduct the enantiodivergent synthesis of axially chiral biphenyl compounds in high chemical and optical yields.
Chiral monodentate phosphines and bulky carboxylic acids: Cooperative effects in palladium-catalyzed enantioselective C(sp3)-H functionalization
Saget, Tanguy,Lemouzy, Sebastien J.,Cramer, Nicolai
, p. 2238 - 2242 (2012)
Teaming up: The important indoline scaffold is provided with enantiomeric ratios of up to 98:2 in palladium(0)-catalyzed C(sp3)-H activations of aryl triflates. The key is the combination of the electron-rich monodentate Sagephos and the bulky 9H-xanthene-9-carboxylic acid. Both participate in a highly cooperative manner in the enantiodetermining concerted-deprotonation- metalation step (see scheme, Tf=triflate). Copyright
Enantioselective Synthesis of Atropisomeric Biaryls using Biaryl 2,5-Diphenylphospholanes as Ligands for Palladium-Catalysed Suzuki-Miyaura Reactions
Byrne, Liam,Munday, Rachel H.,Norrby, Per-Ola,Sk?ld, Christian,Smith, Peter D.,Turner, Andrew R.
supporting information, p. 259 - 267 (2020/12/07)
Here we describe the development of biaryl 2,5-diphenylphospholanes as a new class of C2-symmetric, monodentate ligands for asymmetric Suzuki-Miyaura (ASM) reactions. Screening of a series of exemplary phospholanes led to the identification of two ligands that were used to prepare a range of atropisomeric biaryl and heterobiaryl products with good to excellent levels of enantioselectivity (up to 97:3 e.r.) under mild conditions. DFT studies suggest that the formation of a constraining ligand pocket and coordination of one of the biaryl methoxy groups in the optimised ligands to the metal centre is crucial for restricting conformational freedom in the bond-forming step. (Figure presented.).
Isothiourea-Catalyzed Atropselective Acylation of Biaryl Phenols via Sequential Desymmetrization/Kinetic Resolution
Brueckner, Alexander C.,Campbell, Andrew D.,Cheong, Paul Ha-Yeon,Feoktistova, Taisiia,Grove, Markas A.,Munday, Elizabeth S.,Slawin, Alexandra M. Z.,Smith, Andrew D.,Walden, Daniel M.,Young, Claire M.
supporting information, p. 7897 - 7905 (2020/03/23)
Axially chiral phenols are attractive targets in organic synthesis. This motif is central to many natural products and widely used as precursors to, or directly, as chiral ligands and catalysts. Despite their utility few simple catalytic methods are avail
Synthesis and Study of a Dialkylbiaryl Phosphine Ligand; Lessons for Rational Ligand Design
Bryant, Dillon J.,Zakharov, Lev N.,Tyler, David R.
supporting information, (2019/09/12)
The rational design and synthesis of a novel dialkylbiarylphosphine ligand, 2′-(dimethylphosphine)-2,6-dimethoxy-1,1′-biphenyl (MeSPhos), for palladium-catalyzed C-N cross-coupling reactions is described. Based on previous results, it was hypothesized that a ligand with electronic properties similar to (2-biphenyl)dimethylphosphine (MeJPhos) but with greater steric bulk would allow the cross-coupling of previously inaccessible deactivated aryl chlorides. As predicted, MeSPhos exhibited similar electronic properties to MeJPhos. However, MeSPhos surprisingly showed a significantly smaller steric profile than MeJPhos. In comparison to the widely used CySPhos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl), MeSPhos promoted the oxidative addition of highly deactived aryl chlorides for which CySPhos was ineffective, but significantly decreased the rate of reductive elimination. The kinetics of cross-coupling reactions showed that the altered steric and electronic parameters of MeSPhos had a significant impact on the rate of cross-coupling, and the decreased steric bulk had a profound deleterious impact on the catalyst stability. With regard to this latter point, only the most activated aryl chlorides reacted at a sufficient rate to overcome the rate of catalyst decomposition. These results indicate that the relationship between the electron-donating ability of the phosphine ligand and the rate of oxidative addition is complex, and they also illustrate that increasing substitution on the biphenyl structure does not necessarily increase the steric bulk of the ligand.
Site-Selective Cross-Coupling of Remote Chlorides Enabled by Electrostatically Directed Palladium Catalysis
Golding, William A.,Pearce-Higgins, Robert,Phipps, Robert J.
supporting information, p. 13570 - 13574 (2018/10/20)
Control of site-selectivity in chemical reactions that occur remote from existing functionality remains a major challenge in synthetic chemistry. We describe a strategy that enables three of the most commonly used cross-coupling processes to occur with high site-selectivity on dichloroarenes that bear acidic functional groups. We have achieved this by repurposing an established sulfonylated phosphine ligand to exploit its inherent bifunctionality. Mechanistic studies suggest that the sulfonate group engages in attractive electrostatic interactions with the cation associated with the deprotonated substrate, guiding cross-coupling to the chloride at the arene meta position. This counterintuitive combination of anionic ligand and anionic substrate demonstrates an alternative design principle when considering the application of noncovalent interactions to direct catalysis.
Biarylphosphonite gold(I) complexes as superior catalysts for oxidative cyclization of propynyl arenes into indan-2-ones
Henrion, Guilhem,Chavas, Thomas E. J.,Le Goff, Xavier,Gagosz, Fabien
, p. 6277 - 6282 (2013/07/11)
Striking gold: A series of variously functionalized propynyl arenes was smoothly converted into indan-2-ones by a new gold(I)-catalyzed oxidative cyclization process. [LAu]NTf2 (Tf=trifluoromethanesulfonyl) is a superior catalyst both in terms of yield and kinetics for the present transformation. Copyright
Aryne-mediated fluorination: Synthesis of fluorinated biaryls via a sequential desilylation-halide elimination-fluoride addition process
Diemer, Vincent,Garcia, Juan Sanz,Leroux, Frédéric R.,Colobert, Fran?oise
, p. 146 - 155 (2012/02/15)
An unusual aryne-mediated fluorination of aromatic ring systems during the desilylation of ortho-bromo-biphenyl-trimethylsilanes with tetrabutylammonium fluoride (TBAF) is described. In situ formation of an aryne and addition of fluoride affords fluorinat
P-Stereogenic monophosphines in Pd-catalysed enantioselective hydrovinylation of styrene
Grabulosa, Arnald,Mannu, Alberto,Muller, Guillermo,Calvet, Teresa,Font-Bardia, Mercè
experimental part, p. 2338 - 2345 (2011/06/26)
Two groups of P-stereogenic monodentate phosphines containing pendant groups bearing functionalities capable of having secondary interactions, PArPhR (Ar = 2-[(2′,6′-dimethoxy)-1,1′-biphenylyl] and R = OMe (6) or Me (8)) and PMeR(CH2R′) (13, R
Regioselectivity in the aryne cross-coupling of aryllithiums with functionalized 1,2-dibromobenzenes
Diemer, Vincent,Begaud, Manon,Leroux, Frederic R.,Colobert, Fracoise
experimental part, p. 341 - 354 (2011/02/28)
Tri- and tetrasubstituted ortho-bromobiaryls have been synthesized in good-to-excellent yields by aryne cross-coupling reactions starting from 1,3-dimethoxybenzene and functionalized 1,2-dibromobenzenes. This study outlines the influence of the 1,2-dibromobenzene precursor as well as the reaction temperature on the outcome of the aryl-aryl bond formation and indicates, in the case of dissymmetrical benzyne precursors, how structural parameters (electronic effects, steric hindrance, temperature, etc.) control the regioselectivity of the aryne cross-coupling reactions. A wide range of o,o′-tri- and-tetrasubstituted biphenyls have been prepared by a transition-metal-free "aryne" cross-coupling starting from 2,6-dimethoxyphenyllithium and various functionalized 1,2-dibromobenzenes. Mechanistic investigations outline the key parameters that govern both the aryl-aryl bond formation and the regioselectivity of the reaction with dissymmetrical aryne precursors. Copyright
