Ligand Effects in Carboxylic Ester- and Aldehyde-Assisted β-C–H Activation in Regiodivergent and Enantioselective Cycloisomerization–Hydroalkenylation and Cycloisomerization–Hydroarylation, and [2 + 2 + 2]-Cycloadditions of 1,6-Enynes DOI
Kiron Kumar Ghosh, T. V. RajanBabu

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(27), P. 18753 - 18770

Published: June 27, 2024

Herein, we report room temperature, atom-economic protocols for high regio- and enantioselective tandem cycloisomerization–hydroarylation cycloisomerization–hydroalkenylation of 1,6-enynes leading to vicinal carba-functionalized pyrrolidines, tetrahydrofurans, cyclopentanes. The latter steps in these processes involve carbonyl-coordination-assisted ortho-C–H activation aromatic aldehydes esters, and, a similar, yet rarely seen, β-C–H the case acrylates. Synthetically useful versions such reactions are rare limited C2–H indoles pyrroles. A similar reaction is also observed with N-vinylphthalimide, which has carbonyl group suitable C–H activation. dibenzooxaphosphole ligand, (2S,2S′,3S,3S′)-MeO-BIBOP was uniquely identified as crucial achieving challenging enantioselectivity. This methodology gives access substituted five-membered carbo- heterocyclic compounds good yields excellent enantioselectivities under low catalyst loading. primary KIE 3.5 an intermolecular competition experiment methyl benzoate d5-methyl benzoate, indicates that cleavage turnover-limiting step this process. Unlike acrylates, undergoes exclusive hydroalkenylation, β, γ-unsaturated ester, but-3-enoate, highly cycloisomerization-coupling sequence 1,6-enyne giving either [2 + 2 2]-cycloaddition (S, S)-BDPP or hydroalkenylation (2S,2′S,3S,3′S)-MeO-BIBOP depending on ligand employed. (E)-configuration newly formed double bond at terminal alkynyl carbon (of starting enyne) product β,γ-unsaturated ester suggests more classical migratory insertion-β-hydride elimination route formation product.

Language: Английский

Modular Chiral-Aldehyde/Palladium Catalysis Enables Atom-Economical α-Allylation of N-Unprotected Amino Acid Esters with 1,3-Dienes and Allenes DOI
Jianhua Liu, Qing Zhou,

Yao Lin

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(9), P. 6013 - 6022

Published: April 18, 2023

Herein, we report a chiral-aldehyde/palladium-catalyzed atom-economic asymmetric α-allylation of N-unprotected amino acid esters with unsaturated hydrocarbons. Chiral-aldehyde catalysis provides active nucleophilic intermediates from esters, while palladium the electrophilic π-allyl metal species via hydrometallation Accordingly, both 1,3-dienes and allenes can be achieved high efficiency, allowing various α,α-disubstituted unnatural α-amino to generated in good-to-excellent yields stereoselectivities. No N-allylation byproducts are formed these two reactions. Based on results mechanistic control experiments, reaction models proposed. Overall, this work demonstrates completely atom-economical method for preparing structurally diverse chiral acids guidance developing further chiral-aldehyde catalytic systems.

Language: Английский

Citations

20
Atroposelective Synthesis of Axially Chiral Styrenes by Platinum‐ Catalyzed Stereoselective Hydrosilylation of Internal Alkynes DOI

Qimin Wu,

Qi Zhang, Shuxin Yin

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(30)

Published: May 25, 2023

Abstract Hydrofunctionalization of alkynes is one the most efficient ways to access axially chiral styrenes with open‐chained olefins. While great advances have been achieved for 1‐alkynylnaphthalen‐2‐ols and analogues, atroposelective hydrofunctionalization unactivated internal lags. Herein we reported a platinum‐catalyzed hydrosilylation first time. With monodentate TADDOL‐derived phosphonite L1 used as ligand, various were in excellent enantioselectivities high E ‐selectivities. Control experiments showed that N H‐arylamide groups significant effects on both yields could act directing groups. The potential utilities products shown by transformations amide motifs products.

Language: Английский

Citations

20
Visible Light‐Mediated Cobalt and Photoredox Dual‐Catalyzed Asymmetric Reductive Coupling for Axially Chiral Secondary Alcohols† DOI

Tianlong Liang,

Yingtao Wu,

Jiaqiong Sun

et al.

Chinese Journal of Chemistry, Journal Year: 2023, Volume and Issue: 41(23), P. 3253 - 3260

Published: July 20, 2023

Comprehensive Summary Secondary alcohols bearing both axial and central chirality comprise attractive biological activity exhibit excellent chiral induction in asymmetric reactions. However, only very limited catalytic approaches were developed for their synthesis. We herein describe visible light‐mediated cobalt‐catalyzed reductive Grignard‐type addition of aryl iodides with axially prochiral biaryl dialdehydes leading to the direct construction secondary alcohols. Preliminary mechanistic studies indicate that efficient kinetic recognition diastereomers might occur improve stereoselectivity, which open a new avenue challenging cascade multiple elements. This protocol features enantio‐ diastereoselectivity, green mild conditions, simple operation, broad substrate scope, providing modular platform synthesis

Language: Английский

Citations

19
Catalytic Asymmetric Synthesis of Zinc Metallacycles DOI

Hayden D. Bishop,

Qiang Zhao, Christopher Uyeda

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(37), P. 20152 - 20157

Published: Sept. 11, 2023

Transition-metal-catalyzed reductive coupling reactions of alkynes and imines are attractive methods for the synthesis chiral allylic amines. Mechanistically, these involve oxidative cyclization alkyne imine to generate a metallacyclic intermediate, which then reacts with H2 or surrogate form product. As an alternative this hydrogenolysis pathway, here we show that transmetalation zinc can occur, forming metallacycle This organozinc product serves as versatile nucleophile carbon-carbon carbon-heteroatom reactions. Mechanistic studies based on isotopic labeling experiments DFT calculations suggest key step occurs between Co(II) species ZnCl2.

Language: Английский

Citations

18
Pathway-divergent coupling of 1,3-enynes with acrylates through cascade cobalt catalysis DOI Creative Commons
Heng Wang,

Xiaofeng Jie,

Qinglei Chong

et al.

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 23, 2024

Catalytic cascade transformations of simple starting materials into highly functionalized molecules bearing a stereochemically defined multisubstituted alkene, which are important in medicinal chemistry, natural product synthesis, and material science, high demand for organic synthesis. The development multiple reaction pathways accurately controlled by catalysts derived from different ligands is critical goal the field catalysis. Here we report cobalt-catalyzed strategy direct coupling inexpensive 1,3-enynes with two acrylates to construct diversity 1,3-dienes containing trisubstituted or tetrasubstituted olefin. Such reactions can proceed through three initiated oxidative cyclization achieve bond formation chemo-, regio- stereoselectivity precisely ligands, providing platform tandem carbon-carbon bond-forming reactions.

Language: Английский

Citations

7
γ C–H Functionalization of Amines via Triple H-Atom Transfer of a Vinyl Sulfonyl Radical Chaperone DOI
James H. Herbort, Taylor N. Bednar, Andrew D. Chen

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(29), P. 13366 - 13373

Published: July 12, 2022

A selective, remote desaturation has been developed to rapidly access homoallyl amines from their aliphatic precursors. The strategy employs a triple H-atom transfer (HAT) cascade, entailing (i) cobalt-catalyzed metal-HAT (MHAT), (ii) carbon-to-carbon 1,6-HAT, and (iii) Co-H regeneration via MHAT. new class of sulfonyl radical chaperone (to direct remote, reactivity) enables diverse amines, amino acids, peptides with excellent site-, chemo-, regioselectivity. key, enabling C-to-C HAT step in this cascade was computationally designed satisfy both thermodynamic (bond strength) kinetic (polarity) requirements, it probed regioselectivity, isomerization, competition experiments. We have also interrupted dehydrogenation achieve γ-selective C-Cl, C-CN, C-N bond formations.

Language: Английский

Citations

27
Cationic Bis(phosphine) Cobalt(I) Arene Complexes as Precatalysts for the Asymmetric Synthesis of Sitagliptin DOI
Connor S. MacNeil, Hongyu Zhong, Tyler P. Pabst

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(8), P. 4680 - 4687

Published: April 5, 2022

The cobalt-catalyzed asymmetric hydrogenation of dehydro-sitagliptin was studied and applied to the synthesis sitagliptin (Januvia). Catalyst discovery efforts were accelerated by application a general method for cationic bis(phosphine) cobalt η6-arene complexes. One-electron oxidation cobalt(II) dialkyl complexes in presence arenes furnished corresponding, bench-stable precatalysts, [(P–P)Co(η6-C6H6)][BAr4F]. Asymmetric utilized 0.5 mol % optimal catalyst, [(R,R)-(iPrDuPhos)Co(η6-C6H6)][BAr4F], THF solution produced >99% yield with 97% ee. Cobalt catalysts compatible range solvents maintained excellent activity selectivity after standing air solid state 2 weeks. Deuterium labeling studies support an enamine–imine tautomerization process resulting reduction metalated imine. Notably, state-of-the-art neutral precatalysts ineffective, emphasizing utility class precatalysts.

Language: Английский

Citations

25
Mechanism of a cobalt-catalyzed hydroarylation reaction and origin of stereoselectivity DOI
Yang Wang,

Kaili Gong,

Han Zhang

et al.

Catalysis Science & Technology, Journal Year: 2022, Volume and Issue: 12(13), P. 4380 - 4387

Published: Jan. 1, 2022

In the present study, mechanism of a cobalt-catalyzed hydroarylation reaction between N -pyridylindole and 1,6-enynes origin its stereoselectivity have been systematically investigated using DFT calculation method.

Language: Английский

Citations

24
Theoretical investigation on cobalt-catalyzed hydroacylation reaction: Mechanism and origin of stereoselectivity DOI
Yang Wang, Han Zhang, Yue Liu

et al.

Molecular Catalysis, Journal Year: 2022, Volume and Issue: 527, P. 112410 - 112410

Published: June 7, 2022

Language: Английский

Citations

23
Ligand‐Dictated Regiodivergent Allylic Functionalizations via Palladium‐Catalyzed Remote Substitution DOI
Xin Wang,

Han‐Zhe Miao,

Guo‐Qiang Lin

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(28)

Published: March 15, 2023

Different from classical allylic substitutions that require a vicinal leaving group, an olefin bearing remote group is scarcely viewed as potential allylation substrate. Herein, we describe feasible protocols to achieve regiodivergent C-H functionalizations via palladium-catalyzed substitution, which provides novel strategy for the seldomly studied migratory Tsuji-Trost reaction. Dictated by suitable ligand, process involved 4,3-hydrofunctionalization of generated conjugated diene intermediate metal walking observed in generally >20 : 1 regioselectivity. Unexpectedly, related 1,4-hydrofunctionalization pathway found be major route with newly synthesized electron-rich bisphosphine challenges conventional viewpoint on regioselectivity hydrofunctionalizations linear internal dienes η3 -substitution. A series deuterium experiments and kinetic studies provide preliminary insight into catalytic cycle.

Language: Английский

Citations

17