Catalytic Approach toward Chiral P,N-Chelate Complexes Utilizing the Asymmetric Hydrophosphination Protocol

Katona, D.; Lu, Yunpeng; Li, Yongxin; Pullarkat, Sumod A.; Leung, Pak‐Hing

doi:10.1021/acs.inorgchem.9b03549

Cited by 14 publications

(5 citation statements)

References 74 publications

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“…As part of our continuing efforts to develop more efficient strategies to access chiral phosphine derivatives, we have made progressive insights into implementing the use of optically active air stable phosphapalladacycles, to catalyze the formation of a wide array of chiral tertiary phosphines through an asymmetric hydrophosphination (AHP) pathway . This process circumvents the accompanying difficulties ascribed to the above-mentioned methodologies and enables the furnishing of phosphine adducts within a one-pot single-step process with high atom economy, starting from completely achiral materials …”

Section: Introductionmentioning

confidence: 61%

Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Foo

Sadeer

et al. 2021

Organometallics

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A series of PN(sp 2)P ligands containing two stereogenic carbon centers were generated via the palladium(II) catalyzed asymmetric hydrophosphination of 2,6-pyridyl dienones using diphenylphosphine. Although the targeted tridentate products are powerful metal ion sequesters, poisoning of the metal catalyst due to irreversible chelation by the adducts during the course of the addition reaction was circumvented via this protocol. The reported procedure thus enabled the efficient access toward chiral PN(sp 2)P pincer-type ligands in a one-pot, single-step process with good conversions and high enantioselectivities. The formed ligands can be further coordinated to various metal centers to form chiral PNP complexes with potential synthetic applications.

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Section: Introductionmentioning

confidence: 61%

Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Foo

Sadeer

et al. 2021

Organometallics

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“…The 31 P{ 1 H} NMR spectrum of complex 6 exhibits two doublet of doublets at 245.3 ( 1 J P–Rh = 276.2, 2 J P–P = 33.5 Hz) and 55.7 ppm ( 1 J P–Rh = 144.0, 2 J P–P = 32.4 Hz), suggesting that the two phosphorus nuclei are chemically inequivalent. Moreover, the small 2 J P–P coupling constant indicates that both ligands are cis -oriented in solution, akin to a related square planar Rh(Cl)(PPh 3 ) complex with an additional chiral isoquinoline phosphine P,N-type ligand ( 2 J P–P = 41.6 Hz) . The two benzylic protons are diastereotopic, showing two sets of signals with a large 2 J H–H coupling of ca.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Coordination Chemistry, and Mechanistic Studies of P,N-Type Phosphaalkene-Based Rh(I) Complexes

et al. 2022

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The synthesis of P,N-phosphaalkene ligands, py-CHPMes* (1, py = 2-pyridyl, Mes* = 2,4,6-tBu–C6H2) and the novel quin-CHPMes* (2, quin = 2-quinolinyl) is described. The reaction with [Rh(μ-Cl)cod]2 produces Rh(I) bis(phosphaalkene) chlorido complexes 3 and 4 with distorted trigonal bipyramidal coordination environments. Complexes 3 and 4 show a pronounced metal-to-ligand charge transfer (MLCT) from Rh into the ligand PC π* orbitals. Upon heating, quinoline-based complex 4 undergoes twofold C–H bond activation at the o-tBu groups of the Mes* substituents to yield the cationic bis(phosphaindane) Rh(I) complex 5, which could not be observed for the pyridine-based analogue 3. Using sub- or superstoichiometric amounts of AgOTf the C–H bond activation at an o-tBu group of one or at both Mes* was detected, respectively. Density functional theory (DFT) studies suggest an oxidative proton shift pathway as an alternative to a previously reported high-barrier oxidative addition at Rh(I). The Rh(I) mono- and bis(phosphaindane) triflate complexes 6 and 7, respectively, undergo deprotonation at the benzylic CH2 group of the phosphaindane unit in the presence of KOtBu to furnish neutral, distorted square-planar Rh(I) complexes 8 and 9, respectively, with one of the P,N ligands being dearomatized. All complexes were fully characterized, including multinuclear NMR, vibrational, and ultraviolet–visible (UV–vis) spectroscopy, as well as single-crystal X-ray and elemental analysis.

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“…In addition, axial heterobiaryl compounds are also present in many FDA-approved drugs, and they have been proven to have a positive contribution to pharmacokinetics including absorption, distribution, metabolism, excretion, and potency via interaction with the target protein, which made heterobiaryl molecules more and more prevalent in drug discovery and drug development ( Figure 1 B) [ 17 , 18 , 19 , 20 , 21 ]. In addition, axially chiral heterobiaryl subunits, such as isoquinoline containing phosphine and atropisomeric isoquinoline N -oxide, have been successfully employed as powerful chiral ligands to construct various chiral molecules through transition-metal catalyzed asymmetric transformation ( Figure 1 C) [ 22 , 23 , 24 , 25 , 26 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

Advances in Atroposelectively De Novo Synthesis of Axially Chiral Heterobiaryl Scaffolds

et al. 2022

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Axially chiral heterobiaryl frameworks are privileged structures in many natural products, pharmaceutically active molecules, and chiral ligands. Therefore, a variety of approaches for constructing these skeletons have been developed. Among them, de novo synthesis, due to its highly convergent and superior atom economy, serves as a promising strategy to access these challenging scaffolds including C–N, C-C, and N-N chiral axes. So far, several elegant reviews on the synthesis of axially chiral heterobiaryl skeletons have been disclosed, however, atroposelective construction of the heterobiaryl subunits by de novo synthesis was rarely covered. Herein, we summarized the recent advances in the catalytic asymmetric synthesis of the axially chiral heterobiaryl scaffold via de novo synthetic strategies. The related mechanism, scope, and applications were also included.

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Catalytic Approach toward Chiral P,N-Chelate Complexes Utilizing the Asymmetric Hydrophosphination Protocol

Cited by 14 publications

References 74 publications

Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Synthesis, Coordination Chemistry, and Mechanistic Studies of P,N-Type Phosphaalkene-Based Rh(I) Complexes

Advances in Atroposelectively De Novo Synthesis of Axially Chiral Heterobiaryl Scaffolds

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Catalytic Approach toward Chiral P,N-Chelate Complexes Utilizing the Asymmetric Hydrophosphination Protocol

Cited by 14 publications

References 74 publications

Access to C-Stereogenic PN(sp2)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Access to C-Stereogenic PN(sp2)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Synthesis, Coordination Chemistry, and Mechanistic Studies of P,N-Type Phosphaalkene-Based Rh(I) Complexes

Advances in Atroposelectively De Novo Synthesis of Axially Chiral Heterobiaryl Scaffolds

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Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination

Access to C-Stereogenic PN(sp²)P Pincer Ligands via Phosphapalladacycle Catalyzed Asymmetric Hydrophosphination