Cobalt-Catalyzed Migration Isomerization of Dienes DOI

Jiajin Zhao,

Guo-Xiong Xu,

Xue Wang

et al.

Organic Letters, Journal Year: 2022, Volume and Issue: 24(25), P. 4592 - 4597

Published: June 21, 2022

A cobalt-catalyzed multipositional isomerization of conjugated dienes has been reported for the first time using an 8-oxazoline iminoquinoline ligand. This reaction is operationally simple and atom-economical readily available starting materials with E/Z mixture to access disubstituted 1,3-dienes excellent yields good E,E stereoselectivity. The mechanism via alkene insertion cobalt hydride species β-H elimination a π-allyl intermediate proposed on basis deuterium labeling control experiments density functional theory calculations.

Language: Английский

Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes DOI
Sheng Zhang, Deepika Bedi, Lu Cheng

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(19), P. 8910 - 8917

Published: April 21, 2020

Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization 1,1-disubstituted can serve as an alternative approach alkenes, but it remains underdeveloped owing issues relating reaction efficiency stereoselectivity. Here we show that novel cobalt catalyst overcome these challenges provide efficient stereoselective access broad range alkenes. This protocol compatible both mono- dienes exhibits good functional group tolerance scalability. Moreover, has proven be useful tool construct luminophores deuterated alkene. A preliminary study mechanism suggests cobalt-hydride pathway involved reaction. The high stereoselectivity attributed π–π stacking effect steric hindrance substrate catalyst.

Language: Английский

Citations

88
Iron-Catalyzed Tunable and Site-Selective Olefin Transposition DOI
Xiaolong Yu, Haonan Zhao, Ping Li

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(42), P. 18223 - 18230

Published: Sept. 29, 2020

The catalytic isomerization of C–C double bonds is an indispensable chemical transformation used to deliver higher-value analogues and has important utility in the industry. Notwithstanding advances reported this field, there compelling demand for a general solution that enables precise control C═C bond migration position, both cyclic acyclic systems, furnish disubstituted trisubstituted alkenes. Here, we show amounts appropriate earth-abundant iron-based complex, base boryl compound, promote efficient controllable alkene transposition. Mechanistic investigations reveal these processes likely involve situ formation iron-hydride species which promotes olefin through sequential insertion/β-hydride elimination. Through strategy, regiodivergent access different products from one substrate can be facilitated, isomeric mixtures commonly found petroleum-derived feedstock transformed single product, unsaturated moieties embedded within linear heterocyclic biologically active entities obtained.

Language: Английский

Citations

76
Stereodivergent, Kinetically Controlled Isomerization of Terminal Alkenes via Nickel Catalysis DOI Creative Commons
Camille Rubel, Anne K. Ravn, Hang Chi Ho

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 18, 2024

Abstract Because internal alkenes are more challenging synthetic targets than terminal alkenes, metal‐catalyzed olefin mono‐transposition (i.e., positional isomerization) approaches have emerged to afford valuable E ‐ or Z‐ from their complementary alkene feedstocks. However, the applicability of these methods has been hampered by lack generality, commercial availability precatalysts, and scalability. Here, we report a nickel‐catalyzed platform for stereodivergent / Z ‐selective synthesis at room temperature. Commercial reagents enable this one‐carbon transposition ‐internal via Ni−H‐mediated insertion/elimination mechanism. Though mechanistic regime is same in both systems, underlying pathways that lead each active catalysts distinct, with catalyst forming comproportionation an oxidative addition complex followed substrate protonation metal trialkylphosphonium salt additive. In case, ligand sterics denticity control stereochemistry prevent over‐isomerization.

Language: Английский

Citations

12
Highly Z-Selective Double Bond Transposition in Simple Alkenes and Allylarenes through a Spin-Accelerated Allyl Mechanism DOI
Daniel Kim,

Guy Pillon,

Daniel J. DiPrimio

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(8), P. 3070 - 3074

Published: Feb. 17, 2021

Double-bond transposition in alkenes (isomerization) offers opportunities for the synthesis of bioactive molecules, but requires high selectivity to avoid mixtures products. Generation Z-alkenes, which are present many natural products and pharmaceuticals, is particularly challenging because it usually less thermodynamically favorable than generation E isomers. We report a β-dialdiminate-supported, high-spin cobalt(I) complex that can convert terminal alkenes, including previously recalcitrant allylbenzenes, Z-2-alkenes with unprecedentedly regioselectivity stereoselectivity. Deuterium labeling studies indicate catalyst operates through π-allyl mechanism, different from alkyl mechanism followed by other Z-selective catalysts. Computations triplet alkene undergoes spin state change resting-state singlet lowest-energy C–H activation transition state, leads Z product. This suggests this enables differentiate stereodefining barriers system, more generally spin-state changes may offer route toward novel stereocontrol methods first-row metals.

Language: Английский

Citations

50
Cobalt-Catalyzed Desymmetric Isomerization of Exocyclic Olefins DOI

Xufang Liu,

Xianle Rong, Shihan Liu

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(49), P. 20633 - 20639

Published: Dec. 6, 2021

Chiral cyclic olefins, 1-methylcyclohexenes, are versatile building blocks for the synthesis of pharmaceuticals and natural products. Despite prevalence these structural motifs, development efficient synthetic methods remains an unmet challenge. Herein we report a novel desymmetric isomerization exocyclic olefins using series newly designed chiral cobalt catalysts, which enables straightforward construction 1-methylcyclohexenes with diversified functionalities. The utility this methodology is highlighted by concise enantioselective product, β-bisabolene. versatility reaction products further demonstrated multifarious derivatizations.

Language: Английский

Citations

45
Synergistic Hydrocobaltation and Borylcobaltation Enable Regioselective Migratory Triborylation of Unactivated Alkenes DOI
Yinsong Zhao, Shaozhong Ge

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(14)

Published: Jan. 28, 2022

The structural diversity of sp3 -triorganometallic reagents enhances their potentiality in the modular construction molecular complexity chemical synthesis. Despite significant achievements on preparation 1,1,1- and 1,1,2-triorganometallic B,B,B-reagents, catalytic approaches that enable installation multiple boryl groups at skipped carbons unactivated alkenes still remain elusive. Herein, we report a cobalt-catalyzed selective triborylation reaction to access synthetically versatile 1,1,3-triborylalkanes. This protocol provides general platform for regioselective trifunctionalization alkenes, its utility is highlighted by synthesis various value-added chemicals from readily accessible alkenes. Mechanistic studies, including deuterium-labelling experiments evaluation potential reactive intermediates, provide insight into experimentally observed chemo- regioselectivity.

Language: Английский

Citations

39
Cobalt-Catalyzed Enantioconvergent Hydrogenation of Minimally Functionalized Isomeric Olefins DOI
Peng Lu, Hongliang Wang,

Yihui Mao

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(38), P. 17359 - 17364

Published: Sept. 15, 2022

Investigation on asymmetric hydrogenation of olefins is great importance in both pharmaceutical molecule synthesis and chemical industry due to the high demand for enantiopure compounds. The established methods often require geometrically pure olefins. enantioconvergent reaction provided possibility access a single stereoisomer via E/Z-olefin mixtures; however, polar functional group next carbon-carbon double bond was usually necessary. Here, we reported cobalt-catalyzed readily available minimally functionalized mixtures. This strategy shows good tolerance provides an alternative means transformation. preliminary mechanistic studies indicated that isomerization key achieve convergent

Language: Английский

Citations

39
(Z)-Selective Isomerization of 1,1-Disubstituted Alkenes by Scandium-Catalyzed Allylic C–H Activation DOI
Shao‐Jie Lou, Pan Wang, Xin Wen

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(39), P. 26766 - 26776

Published: Sept. 20, 2024

The isomerization of 1,1-disubstituted alkenes through 1,3-hydrogen shift is an atom-efficient route for synthesizing trisubstituted alkenes, which are important moieties in many natural products, pharmaceuticals, and organic materials. However, this reaction often encounters regio- stereoselectivity challenges, typically yielding

Language: Английский

Citations

8
Part per million levels of an anionic iron hydride complex catalyzes selective alkene isomerization via two-state reactivity DOI Creative Commons
Subhash Garhwal,

Alexander Kaushansky,

Natalia Fridman

et al.

Chem Catalysis, Journal Year: 2021, Volume and Issue: 1(3), P. 631 - 647

Published: June 7, 2021

Language: Английский

Citations

41
Pincer Iron Hydride Complexes for Alkene Isomerization: Catalytic Approach to Trisubstituted (Z)-Alkenyl Boronates DOI

Songgen Xu,

Peiyu Geng,

Yuling Li

et al.

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(16), P. 10138 - 10147

Published: July 30, 2021

An iron dichloride complex [Fe]Cl2 supported by a pincer phosphine–pyridine–imidazoline (PNNimid) ligand {[Fe]Cl2 = (PNNimid)FeCl2}, upon activation with NaHBEt3, catalyzes the isomerization of 1,1-disubstituted alkenyl boronates to synthetically valuable but previously difficult-to-access trisubstituted (Z)-alkenyl excellent regio- and stereoselectivity. The loading catalyst activator relative was found affect selectivity catalytic efficiency. In situ solvent-assisted electrospray ionization mass (SAESI-MS) studies revealed generation two catalytically competent species depending on Fe/NaHBEt3 ratios: reaction 1.5 equiv NaHBEt3 predominantly formed monohydride chloride [Fe]HCl, while treatment 3 furnished dihydride [Fe]H2. addition, alkyl intermediates resulting from insertion boronate into Fe–H bonds [Fe]HCl [Fe]H2 were successfully captured SAESI-MS. hydride catalysts are sensitive steric properties alkene substrates: is efficient for synthesis less hindered alkyl-bearing boronates, whereas favorable sterically more demanding aryl-substituted products. synthetic utility these products demonstrated stereoselective multisubstituted conjugated dienes cyercene A.

Language: Английский

Citations

35