Enantioselective Formal Vinylogous N–H Insertion of Secondary Aliphatic Amines Catalyzed by a High-Spin Cobalt(II) Complex

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(25), С. 9648 - 9656

Опубликована: Июнь 21, 2021

Vinylcarbene insertion into the nitrogen–hydrogen (N–H) bond of amines allows direct access to α,β-unsaturated γ-amino acid derivatives, meeting a marked challenge in control regio- and enantioselectivities. Here, we report highly γ-selective enantioselective N–H bonds aliphatic or aromatic secondary with vinyl substituted α-diazo pyrazoleamides using high-spin chiral N,N′-dioxide/cobalt(II) complex catalyst. The method affords wide variety valuable optically active Z- E-type amides. Calculation reveals spin state change from quartet cobalt(II) doublet Co(II)-carbene species for facile Z-selective nucleophilic addition.

Язык: Английский

---

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

---

Metal-catalysed reactions enabled by guanidine-type ligands

Organic & Biomolecular Chemistry, Год журнала: 2019, Номер 17(19), С. 4689 - 4699

Опубликована: Янв. 1, 2019

A review of metal–guanidine complexes, which are selective and powerful catalysts for organic transformations, asymmetric synthesis, polymerisation.

Язык: Английский

---

Visible-Light-Promoted Site-Selective N¹-Alkylation of Benzotriazoles with α-Diazoacetates

Organic Letters, Год журнала: 2020, Номер 22(18), С. 7284 - 7289

Опубликована: Сен. 9, 2020

A visible-light-promoted highly site-selective N1-alkylation of benzotriazoles with diazo compounds has been achieved under mild and metal-free conditions. Using cheap, readily available p-benzoquinone (PBQ) as a catalyst, wide range are reacted, providing N1-alkylated in moderate to excellent yields N1-selectivities. Preliminary mechanistic studies suggest that radical process accounts for the exclusive site-selectivity this transformation.

Язык: Английский

---

Silver(I)/Dirhodium(II) Catalytic Platform for Asymmetric N–H Insertion Reaction of Heteroaromatics

Journal of the American Chemical Society, Год журнала: 2023, Номер 146(1), С. 733 - 741

Опубликована: Дек. 27, 2023

Transition-metal-catalyzed enantioselective N–H insertion reactions of carbene species offer a powerful and straightforward strategy to produce chiral nitrogen-containing compounds. Developing highly selective using indole variants can meet synthetic demand. Herein we present an asymmetric reaction into bonds the aromatic heterocycles donor/acceptor-substituted diazo compounds based on heteronuclear catalytic platform. Although previously developed catalysis comprising silver catalyst or dirhodium(II,II) paddlewheel complexes with without phosphoric acid showed modest performance, unique combination widely available Rh2(OAc)4 silver(I) phosphate dimer [(S)-TRIP-Ag]2 enabled (up 98% ee). Moreover, Ag/Rh system facilitated regioselective C–H functionalization protic indoles. Mechanistic investigation density functional theory indicated that in situ-generated Ag–Rh trimetallic enolate is protonated environment.

Язык: Английский

---

Copper-Catalyzed Sulfur Alkylation of Sulfenamides with N-Sulfonylhydrazones

Organic Letters, Год журнала: 2024, Номер 26(18), С. 3906 - 3910

Опубликована: Апрель 29, 2024

Sulfilimines are valuable compounds in both organic synthesis and pharmaceuticals. In this study, we present a copper-catalyzed sulfur alkylation of sulfenamides with

Язык: Английский

---

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

---

Rh‐Catalyzed Chemodivergent [3+3] Annulations of Diazoenals and α‐Aminoketones: Direct Synthesis of Functionalized 1,2‐Dihydropyridines and Fused 1,4‐Oxazines

Chemistry - A European Journal, Год журнала: 2024, Номер 30(19)

Опубликована: Янв. 2, 2024

Novel rhodium-catalyzed [3+3] annulations of diazoenals and α-amino ketones has been disclosed here. The reactivity switched from carbenoid to vinylogous NH-insertion by altering acyclic cyclic ketones. In this direction, we report an efficient strategy synthesize 1,2-dihydropyridines (DHPs) fused 1,4-oxazines. Mechanistic investigation revealed that the formyl group is necessary for annulation cyclohexyl dictating factor NH- insertion. synthetic utility was demonstrated synthesizing piperidine, pyrido[1,2-a]indole, 2-pyridone scaffolds. Further, structural diversification 1,4-oxazines resulted in short synthesis hexahydroquinolin-2(1H)-ones, hexahydro quinolines tetrahydroquinolinones via ring opening rearrangement a new oxidative deformylation, respectively.

Язык: Английский

---

Catalyst-free electro-photochemical insertion reactions of carbene anion radicals by convergent paired electrolysis

Cell Reports Physical Science, Год журнала: 2024, Номер 5(5), С. 101944 - 101944

Опубликована: Май 1, 2024

Paired electrolysis is an energy-efficient electrochemical reaction where both anodic and cathodic electron flow directly induces product formation with maximum faradaic efficiency. Herein we report a metal-free convergent pair electro-photochemical strategy to generate radical cation anion that resulted in the N-alkylation of various N-heterocycles, amines, sulfonamides. The also facilitated site-selective CH-alkylation benzo fused morpholine, indolines, OH- SH- alkylation phenols thiophenols aryl diazo esters. Mild condition such as 5 mA constant current W blue LED were sufficient complete within 2 h. Late-stage APIs sulfadiazines privileged scaffolds like sulfonamides diazepanes have been achieved successfully. This paired photo-electrolysis establishes new way achieve important reactions better productivity shorter time over existing strategies.

Язык: Английский

---

Scandium(III) Triflate Catalyzed Direct Synthesis of N-Unprotected Ketimines

Organic Letters, Год журнала: 2019, Номер 22(1), С. 120 - 125

Опубликована: Дек. 19, 2019

N-Unprotected ketimines are useful substrates and intermediates for synthesizing valuable nitrogen-containing compounds, but their potential applicability is limited by the available synthetic methods. To address this issue, we report a scandium(III) triflate catalyzed direct synthesis of N-unprotected ketimines. Using commercially reagents Lewis acid catalysts, ketones were directly transformed into corresponding in high yields with broad functional group tolerance, even multigram scales. The reactions readily applicable one-pot important compounds such as glycine Schiff base without isolation ketimine intermediates. Preliminary mechanistic studies to clarify reaction mechanism also described.

Язык: Английский

---