Cationic Chiral Pd‐Catalyzed “Acetylenic” Diels–Alder Reaction: Computational Analysis of Reversal in Enantioselectivity

Honda, Kazumasa; Ohkura, Shun; Hayashi, Yoshihiro; Kawauchi, Susumu; Mikami, Kōichi

doi:10.1002/asia.201801035

Cited by 10 publications

(6 citation statements)

References 43 publications

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“…This versatile reaction has been widely employed in modern synthetic chemistry . Various chiral Lewis acid catalysts, such as B, Cu, Mg, Zn, Al, Pd, Ni, Ru, and lanthanide complexes, have been reported to catalyze asymmetric Diels–Alder reactions. Due to the increasing demands for green and sustainable chemistry, the development of environmentally benign metal complex-catalyzed asymmetric reactions are currently receiving increased attention.…”

Section: Introductionmentioning

confidence: 99%

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

et al. 2022

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An efficient iron-catalyzed asymmetric [4 + 2] cycloaddition of cyclopentadiene with α,β-unsaturated acyl imidazoles or 2-cinnamoylisoindoline-1,3-dione derivatives was developed to afford the addition products in high yield and selectivity. Interestingly, the absolute structures of the addition products were controlled by the auxiliaries via different coordination modes with the same type of catalyst.

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Section: Introductionmentioning

confidence: 99%

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

et al. 2022

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“…We tried to prepare monodeuterated 1 through ester pyrolysis of several suitable precursors 59 (Scheme S1), hoping to use the OH group as an NIR antenna for remote rotamerization. 60 This would have allowed an indirect probe of the leak process because the heavier 2 H-1cc isotopomer could not dissociate by QMT while rotamerization would still occur at approximately 50% of the rate of the parent molecule.…”

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confidence: 99%

Identification and Reactivity of s-cis,s-cis-Dihydroxycarbene, a New [CH₂O₂] Intermediate

et al. 2020

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We report the first preparation of the s-cis,s-cis conformer of dihydroxycarbene (1cc) by means of pyrolysis of oxalic acid, isolation of the lower-energy s-trans,s-trans (1tt) and s-cis,s-trans (1ct) product conformers at cryogenic temperatures in a N 2 matrix, and subsequent narrow-band near-infrared (NIR) laser excitation to give 1cc. Carbene 1cc converts quickly to 1ct via quantum-mechanical tunneling with an effective half-life of 22 min at 3 K. The potential energy surface features around 1 were pinpointed by convergent focal point analysis targeting the AE-CCSDT(Q)/CBS level of electronic structure theory. Computations of the tunneling kinetics confirm the time scale of the 1cc → 1ct rotamerization and suggest that direct 1cc → H 2 + CO 2 decomposition may also be a minor pathway. The intriguing latter possibility cannot be confirmed spectroscopically, but hints of it may be present in the measured kinetic profiles.

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“…Second, HALD is produced after the hydrogenation of the CC group on CAL (Step 2) and simultaneously the vacant coordination site of Pd(II) activates methanol solvent. The existing Pd(II) Lewis acid sites in the [CpPd(II)Cl] 2 ligands promote the subsequent acetalization reaction without the use of any acid . Afterward, aldehyde intermediate is thought to initially bind to Pd(II) through the interaction between positive charged Pd(II) and carbonyl group (Step 3).…”

Section: Resultsmentioning

confidence: 99%

Pd Nanoparticles Capped with [CpPd(II)Cl]₂ Complexes for Hydrogenation and Acid-Free Acetalization of α,β-Unsaturated Aldehydes

Zhao

Zhou

et al. 2019

ACS Appl. Nano Mater.

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Hierarchical bottom-up self-assembly of nanoparticles by wet chemistry methods is a promising approach to the preparation of engineered metal–ligand networks with advanced catalytic properties. Here, we developed a facile strategy to synthesize self-organized metal–ligand Pd(0)–[CpPd(II)Cl]2 nanoreactor through a redox and in situ transmetalation reaction between palladium ions and titanium ions. The obtained integrated metallic Pd(0) nanoparticles with organic [CpPd(II)Cl]2 capping ligands have been systematically characterized. The self-assemblies can not only serve as a support providing physical barriers against aggregation of ultrasmall Pd nanoparticles with good stability while keeping Pd nanoparticle core highly accessible but can also act as an efficient bifunctional nanoreactor for the first realization of selective hydrogenation and acid-free acetalization cascade reaction. Because of the combination of the two functions of metallic Pd(0) nanoparticles and Lewis acid Pd(II) ions in the [CpPd(II)Cl]2 ligands, the obtained integrated Pd(0)–[CpPd(II)Cl]2 nanoreactor exhibits excellent hydrogenation selectivity and activity (up to 66%–98% yield) in the synthesis of the acetal derivatives from broad substrates of α,β-unsaturated aldehydes and alcohols under mild conditions. Our work has successfully engineered a metal–ligand ensemble to obtain an attractive bifunctional heterogeneous catalyst for cascade organic transformations, presenting a significant step toward the attainment of green and sustainable chemical reactions.

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Cationic Chiral Pd‐Catalyzed “Acetylenic” Diels–Alder Reaction: Computational Analysis of Reversal in Enantioselectivity

Cited by 10 publications

References 43 publications

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

Identification and Reactivity of s-cis,s-cis-Dihydroxycarbene, a New [CH₂O₂] Intermediate

Pd Nanoparticles Capped with [CpPd(II)Cl]₂ Complexes for Hydrogenation and Acid-Free Acetalization of α,β-Unsaturated Aldehydes

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Cationic Chiral Pd‐Catalyzed “Acetylenic” Diels–Alder Reaction: Computational Analysis of Reversal in Enantioselectivity

Cited by 10 publications

References 43 publications

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

Fe-BPsalan Complex-Catalyzed Asymmetric [4 + 2] Cycloaddition of Cyclopentadiene with α,β-Unsaturated Heterocycles

Identification and Reactivity of s-cis,s-cis-Dihydroxycarbene, a New [CH2O2] Intermediate

Pd Nanoparticles Capped with [CpPd(II)Cl]2 Complexes for Hydrogenation and Acid-Free Acetalization of α,β-Unsaturated Aldehydes

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Product

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Identification and Reactivity of s-cis,s-cis-Dihydroxycarbene, a New [CH₂O₂] Intermediate

Pd Nanoparticles Capped with [CpPd(II)Cl]₂ Complexes for Hydrogenation and Acid-Free Acetalization of α,β-Unsaturated Aldehydes