Organoboron Reagents in the Preparation of Functionalized ?-Amino Acids

2007 ◽  
Vol 60 (11) ◽  
pp. 799 ◽  
Author(s):  
Peter F. Kaiser ◽  
Quentin I. Churches ◽  
Craig A. Hutton
Keyword(s):  
Amino Acids ◽  
Cyclic Peptide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Side Chain ◽  
Coupling Reactions ◽  
The Past ◽  
Cross Coupling Reactions ◽  
Metal Catalyzed ◽  
Unsaturated Amino Acids

Over the past decade, major advances in the preparation and utilization of organoboron reagents have been applied to virtually all areas of organic synthesis. The present review collates recent examples of the use of organoboron reagents in the synthesis of α-amino acids and their derivatives. Aryl- and alkenylboronic acids have been used in the asymmetric synthesis of α-amino acids through conjugate addition to unsaturated amino acids and the Petasis three-component coupling reaction. Additionally, α-amino acid derivatives with organoboron functionality on the side-chain have been prepared and used in metal-catalyzed cross-coupling reactions to prepare cross-linked amino acids and complex cyclic peptide natural products.

Review on green chemistry — Suzuki cross coupling in aqueous media

2005 ◽  
Vol 83 (3) ◽  
pp. 266-272 ◽  
Author(s):  
Robert Franzén ◽  
Youjun Xu
Keyword(s):  
Green Chemistry ◽  
Aqueous Media ◽  
Suzuki Reaction ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Aqueous Synthesis ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Metal Catalyzed

The Suzuki cross-coupling reaction is a very efficient, reliable, and environmentally friendly method for the introduction of novel carbon–carbon bonds into molecules. This review summarizes recent advances in the use of the reaction in aqueous media with a focus on different types of ligands and the ligandless protocols currently in use. Several synthetic targets for the reaction have been mentioned. The work summarizes recent results from studies on asymmetric Suzuki reactions performed in organic – aqueous mixed solvents.Key words: Suzuki reaction, green chemistry, metal-catalyzed cross-coupling reactions, aqueous synthesis media.

meta- and para-Functionalized Thermally Crosslinkable OLED-Materials through Selective Transition-Metal-Catalyzed Cross-Coupling Reactions

Synthesis ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 4489-4499
Author(s):  
Michael Reggelin ◽  
Matthias Hempe ◽  
Lutz Schnellbächer ◽  
Tobias Wiesner
Keyword(s):  
Transition Metal ◽  
Thermal Sensitivity ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Synthetic Approach ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Dsc Measurements ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Herein, a synthetic approach using selective transition-metal-catalyzed cross-coupling reactions to thermally crosslinkable OLED materials­ based on vinyl-functionalized arylamines is reported. In a modular approach, 9,9-dialkyl-2,7-diiodo-9H-fluorene underwent a selective Ullmann cross-coupling reaction with bromo-substituted-diphenylamines to give 9,9-dialkyl-2,7-bis(bromo-substituted-diphenylamino)-9H-fluorenes that underwent end-functionalization by the Suzuki–Miyaura reaction using potassium vinyltrifluoroborate to give the corresponding 9,9-dialkyl-2,7-bis(vinyl-substituted-diphenylamino)-9H-fluorenes. Novel meta-functionalized materials were synthesized, which are difficult to prepare by traditional synthetic pathways. The thermal behavior of the compounds was investigated by DSC measurements, indicating a lower thermal sensitivity of the meta-substituted materials than their para-functionalized analogues.

scholarly journals Computational Chemistry and Non-noble Metal-catalyzed Cross-coupling Reaction Mechanisms

2020 ◽  
Vol 74 (6) ◽  
pp. 467-469
Author(s):  
Jeremy N. Harvey ◽  
Andrea Darù
Keyword(s):  
Computational Chemistry ◽  
Noble Metal ◽  
Reaction Mechanisms ◽  
Noble Metals ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Metal Catalyzed

This short overview discusses the contribution that computational methods can make to the study of reaction mechanisms in non-noble-metal-catalyzed cross-coupling reactions. The differences between such reactions and those catalyzed by more traditional noble metals are emphasized, together with the challenge this poses to computation.

scholarly journals Chemoselective nickel-catalyzed coupling through substrate photoexcitation

2021 ◽  
Author(s):  
Pradipta Das ◽  
Eliot Woods ◽  
Jack Ly ◽  
Jack Olding ◽  
Kayla Presley ◽  
...  
Keyword(s):  
Excited State ◽  
Transition Metal ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Ni Catalyst ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Metal Catalyzed ◽  
Coupling Mechanisms

Metallaphotoredox catalysis combines the well-established mechanisms of transition-metal-catalyzed cross-coupling reactions with one-electron redox manipulations enabled by light. In most cases, a transition metal or organic dye serves as the photoredox catalyst while a ground-state Pd or Ni catalyst performs the organometallic steps. Cross-coupling mechanisms that rely on direct photoexcitation of a light-absorbing substrate have the potential to access distinct mechanisms and deliver unique selectivity based on the substrate’s excited-state properties. In this report, we describe a photoinduced, Ni-catalyzed Suzuki–Miyaura cross coupling reaction that selectively functionalizes BODIPY chromophores, a versatile class of tunable, bright, photostable fluorophores. Using a bis-iodo BODIPY substrate, the selectivity for mono- vs. bis-arylation was found to be governed by a remote substituent that subtly alters the excited-state properties of the substrate. Consistent with a substrate photoexcitation mechanism, high chemoselectivity is also observed in mixtures of chromophores with distinct excited-state properties. This reaction is compatible with a variety of substituted BODIPY chromophores and boronic acids and esters, enabling the rapid synthesis of unsymmetrically-substituted chromophores.

An Iron-Based Catalyst Enables The Enantioconvergent Synthesis of Chiral 1,1-Diarylalkanes Through a Suzuki-Miyaura Cross-Coupling Reaction

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Radical Intermediates ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Boronic Esters ◽  
Carbon Centered Radical ◽  
Iron Based ◽  
High Yields

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

Selectfluor-induced C(sp2)–O coupling reaction of N-substituted anilines with hydroxylamine derivatives

2018 ◽  
Vol 16 (33) ◽  
pp. 6017-6024 ◽  
Author(s):  
Bin Sun ◽  
Shi Yin ◽  
Xiaohui Zhuang ◽  
Can Jin ◽  
Weike Su
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Substituted Anilines ◽  
Metal Free ◽  
Cross Coupling Reactions ◽  
Hydroxylamine Derivatives

We developed a novel metal-free method for the construction of C(sp2)–O bonds via oxidative cross-coupling reactions between various N-substituted anilines and hydroxylamine derivatives just using commercially available Selectfluor as an oxidant.

Synthesis of Marine Polyacetylenes Callyberynes A−C by Transition-Metal-Catalyzed Cross-Coupling Reactions to sp Centers

2006 ◽  
Vol 71 (7) ◽  
pp. 2802-2810 ◽  
Author(s):  
Susana López ◽  
Francisco Fernández-Trillo ◽  
Pilar Midón ◽  
Luis Castedo ◽  
Carlos Saá
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

scholarly journals Protecting group-free, selective cross-coupling of alkyltrifluoroborates with borylated aryl bromides via photoredox/nickel dual catalysis

2015 ◽  
Vol 112 (39) ◽  
pp. 12026-12029 ◽  
Author(s):  
Yohei Yamashita ◽  
John C. Tellis ◽  
Gary A. Molander
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Differential Protection ◽  
Coupling Reactions ◽  
Protecting Group ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Rapid Construction ◽  
Metal Catalyzed

Orthogonal reactivity modes offer substantial opportunities for rapid construction of complex small molecules. However, most strategies for imparting orthogonality to cross-coupling reactions rely on differential protection of reactive sites, greatly reducing both atom and step economies. Reported here is a strategy for orthogonal cross-coupling wherein a mechanistically distinct activation mode for transmetalation of sp3-hybridized organoboron reagents enables C-C bond formation in the presence of various protected and unprotected sp2-hybridized organoborons. This manifold has the potential for broad application, because orthogonality is inherent to the activation mode itself. The diversification potential of this platform is shown in the rapid elaboration of a trifunctional lynchpin through various transition metal-catalyzed processes without nonproductive deprotection or functional group manipulation steps.

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