Enantioselective Synthesis of Axially Chiral Alkylidenecycloalkanes via Copper-Catalyzed Functionalization of Acyl Allenols

ACS Catalysis, Год журнала: 2025, Номер unknown, С. 2351 - 2358

Опубликована: Янв. 24, 2025

Язык: Английский

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Enantio‐ and Diastereoselective Synthesis of Chiral Tetrasubstituted α‐Amino Allenoates Bearing a Vicinal All‐Carbon Quaternary Stereocenter with Dual‐Copper‐Catalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(31)

Опубликована: Июнь 1, 2023

The skeletons of chiral tetrasubstituted allenes bearing a vicinal all-carbon quaternary stereocenter are importance but still challenging to synthesize. Herein, we report enantio- and diastereoselective γ-additions 1-alkynyl ketimines with dual-copper-catalysis under mild conditions, affording α-amino allenoates in high yields (up 99 % yield) excellent enantioselectivities ee) diastereoselectivities >20 : 1 dr). Importantly, the stereodivergent synthesis products was realized by asymmetric γ-addition reaction Grignard reagent promoted epimerization. Moreover, dual-copper-catalyzed reactions were smoothly applied gram-scale adopted introduce allenyl moieties into bioactive molecules. Mechanistic experiments density functional theory (DFT) calculations demonstrated that catalyzed double copper catalysts.

Язык: Английский

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Challenging Task of Ni-Catalyzed Highly Regio-/Enantioselective Semihydrogenation of Racemic Tetrasubstituted Allenes via a Kinetic Resolution Process

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(11), С. 7419 - 7430

Опубликована: Март 6, 2024

The first earth-abundant transition metal Ni-catalyzed highly regio- and enantioselective semihydrogenation of racemic tetrasubstituted allenes via a kinetic resolution process as challenging task was well established. This protocol furnishes expedient access to diversity structurally important enantioenriched chiral allylic molecules with high regio-, enantio-, Z/E-selectivity. Remarkably, this proceeded one carbon–carbon double bond allenes, which regioselective complementary the Rh-catalyzed asymmetric version. Deuterium labeling experiments density functional theory (DFT) calculations were carried out reveal reasonable reaction mechanism explain regio-/stereoselectivity.

Язык: Английский

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Novel Stereo‐Induction Pattern in Pudovik Addition/Phospha‐Brook Rearrangement Towards Chiral Trisubstituted Allenes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(22)

Опубликована: Март 23, 2024

Abstract Despite the significance of chiral allene skeletons in catalysis, organic synthesis and medicinal chemistry et al., there is a scarcity reports on axially allenyl phosphorus compounds. Here, we disclosed an efficient straightforward cascade reaction between ethynyl ketones phosphine oxides, resulting broad array trisubstituted allenes incorporating moiety high yields with excellent stereoselectivities facilitated by peptide‐mimic phosphonium salt (PPS) Additionally, comprehensive series mechanistic experiments have been conducted to elucidate that this proceeds via asymmetric Pudovik addition followed subsequent phospha ‐Brook rearrangement occurs concomitantly kinetic resolution, representing stereospecific protonation process facilitating central‐to‐axial chirality transfer manner. We anticipate our research will pave way for promising exploration novel stereo‐induction pattern addition/ reaction.

Язык: Английский

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Enantioselective Photochemical Carbene Insertion into C–C and C–H Bonds of 1,3-Diketones by a Guanidine-Amide Organocatalyst

ACS Catalysis, Год журнала: 2023, Номер 13(7), С. 4656 - 4666

Опубликована: Март 22, 2023

A visible-light-induced enantioselective free carbene transfer reaction of α-diazoesters with 1,3-diketones is established by utilizing a chiral bifunctional guanidine-amide organocatalyst. Selective insertion into the C–C or C–H bonds 1,3-diketone could be achieved bearing different steric hindrances. The transformations enable preparation series 1,4-diketones quaternary carbon center 2-substituted-1,3-diketones in good enantioselectivities. On basis control experiments and DFT calculation, stepwise triplet coupling pathway suggested. possible mechanism proposed to explain origin high enantioselectivities via hydrogen-bonds electrostatic interactions catalyst.

Язык: Английский

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Chiral guanidine catalyzed cyclization reactions of 1,3-enynes for lactone synthesis: switchable H-bond catalysis

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(10), С. 2897 - 2904

Опубликована: Янв. 1, 2024

Cyclization and 1,4-conjugate addition/cyclization between 2-activated 1,3-enynes azlactones were achieved with chiral guanidine-amides for enol-type activation to yield a range of δ-lactone derivatives.

Язык: Английский

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Access to Tetrahydrothiopyrano[2,3‐b]Indole Derivatives via Zinc‐Catalyzed Asymmetric [3+3] Annulation of Indoline‐2‐Thiones with Yne–Enones

Advanced Synthesis & Catalysis, Год журнала: 2024, Номер 366(8), С. 1770 - 1775

Опубликована: Март 1, 2024

Abstract We report herein an enantioselective [3+3] annulation of indoline‐2‐thiones with yne–enones by chiral dinuclear zinc catalysts via a Brønsted base and Lewis acid cooperative activation model. This transformation proceeded through sequential conjugate addition, allenyl ketone formation intramolecular sulfa‐Michael 6‐ endo ‐trig cyclization. A range enantioenriched tetrahydrothiopyrano[2,3‐ b ]indole derivatives bearing exocyclic double bond were obtained in moderate yields excellent stereoselectivities (up to 20 : 1 dr, 20:1 Z/E ratio 95% ee). Late‐stage functionalization, large‐scale experiment further derivatizations also explored.

Язык: Английский

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Asymmetric Carbene Insertion into Se‐S Bonds by Synergistic Rh(II)/Guanidine Catalysis Involving Chalcogen‐Bond Assistance

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 2, 2024

The efficient construction of chalcogen-atom-based chiral compounds remains a challenge, despite the importance organoselenium and organosulfur in life materials science. Chalcogen atoms can form net attractive interactions called chalcogen bonds, but it is an undeveloped tool to assist asymmetric catalysis. Herein, we report enantioselective insertion platform install stereogenic center bearing selenyl thiocyano functional groups. Our method operates by synergistic catalysis guanidine achiral dirhodium complex three-component or four-component reaction, through Se-S bond into carbene species, competing successfully with spontaneous racemic process showing high regioselectivity. As elucidated spectroscopic experiments computational studies, unique mechanism involving as well hydrogen bonding was established account for enantiocontrol. stereoselectivity holds broad array selenylthiocyanatopropanoates, which showed excellent anti-inflammatory toward IL-1β low cytotoxicity.

Язык: Английский

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Catalytic Enantioselective Nucleophilic Addition to Arynes by a New Quaternary Guanidinium Salt-Based Phase-Transfer Catalyst

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(48), С. 26318 - 26327

Опубликована: Ноя. 14, 2023

Owing to the mild generation methods, arynes have been widely used in synthetic chemistry. However, achieving asymmetric organocatalytic reactions with remains a formidable and infrequent challenge, primarily because these neutral transient species tend spontaneously quench. To address this issue, solid–liquid phase-transfer strategy is devised which speed of could be controlled by situ generated fluoride-based chiral catalyst. In study, we present catalytic enantioselective nucleophilic addition reaction involving arynes, utilizing an amino amide-based guanidinium salt QG•X. Furthermore, demonstrate broad compatibility various cyclic/acyclic β-keto amides, leading creation diverse α-aryl quaternary stereocenters good stereoselectivity. Mechanistic investigations uncovered potential involvement intramolecular cationic–anionic pair HF during ion exchange between QG•X CsF for nucleophile activation aryne generation. Additionally, DFT calculations suggested that observed high levels enantioselectivity can attributed steric repulsion cumulative noncovalent interactions catalysts substrates.

Язык: Английский

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Pd((R)-DTBM-SEGphos)Cl₂-catalyzed kinetic resolution of tertiary propargylic alcohols

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(9), С. 2477 - 2484

Опубликована: Янв. 1, 2024

A variety of optically active tertiary propargylic alcohols and tetrasubstituted 2,3-allenoic acids have been synthesized via a Pd(( R )-DTBM-SEGphos)Cl 2 -catalyzed carboxylative kinetic resolution reaction racemic alcohols.

Язык: Английский

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