Highly Diastereo- and Enantioselective Synthesis of Quinuclidine Derivatives by an Iridium-Catalyzed Intramolecular Allylic Dearomatization Reaction DOI Creative Commons
Lin Huang, Yue Cai, Hui‐Jun Zhang

et al.

CCS Chemistry, Journal Year: 2019, Volume and Issue: 1(1), P. 106 - 116

Published: April 1, 2019

Open AccessCCS ChemistryRESEARCH ARTICLE1 Apr 2019Highly Diastereo- and Enantioselective Synthesis of Quinuclidine Derivatives by an Iridium-Catalyzed Intramolecular Allylic Dearomatization Reaction Lin Huang, Yue Cai, Hui-Jun Zhang, Chao Zheng, Li-Xin Dai Shu-Li You Huang State Key Laboratory Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute Organic University Chinese Academy Sciences, 200032 (China) , Cai Zhang Zheng *Corresponding author: E-mail Address: [email protected] Collaborative Innovation Chemical Science Engineering, Tianjin https://doi.org/10.31635/ccschem.019.20180006 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Asymmetric construction quinuclidine derivatives has been realized iridium-catalyzed allylic dearomatization reaction. The catalytic system, derived from [Ir(cod)Cl]2 the Feringa ligand, tolerates a broad range substrates. A large array can be obtained under mild conditions good excellent yields (68%–96%), diastereoselectivity (up >20/1 dr), enantioselectivity >99% ee). These products feature versatile functional group diversity undergo diverse transformations. model that accounts origin stereoselectivity proposed based on density theory (DFT) calculations. Download figure PowerPoint Introduction Quinuclidine, also named 1-azabicyclo[2.2.2]octane, exists number naturally occurring compounds, biologically active agents, privileged catalysts ligands asymmetric catalysis (Figure 1).1–6 In particular, quinine, kind cinchona alkaloid, recognized as medication treatment malaria babesiosis.7,8 are widely utilized homogeneous or heterogeneous various processes such Morita–Baylis–Hillman reactions,4 Sharpless dihydroxylation reactions,5 phase-transfer reactions.6 Therefore, development synthetic approaches efficient novel is great significance. Figure 1 | Selected natural molecules containing scaffolds. this regard, efforts have devoted new methods toward preparation derivatives.9 Traditionally, scaffolds constructed second-order nucleophilic substitution (SN2) reaction condensation piperidine derivatives.10–12 However, most these reactions racemic chiral auxiliary-assisted processes. formed conveniently introducing substituents into ring,13 but scope method rather limited available source starting materials. Catalytic emerged powerful tool transformation planar aromatic compounds highly enantio-enriched three-dimensional molecules.14–49 our ongoing investigate transition-metal-catalyzed reactions, several straightforward protocols access spiroindolenine spiroindoline were revealed.50–53 Recently, we reported unprecedented synthesis indole-annulated, medium-sized ring tetrahydro-γ-carboline- hexahydroazepino[4,3-b]indole-derived carbonates via cascade Ir-catalyzed dearomatization/retro-Mannich/hydrolysis (Scheme 1a).54 Notably, intermediate I was reactive could not isolated. We envisaged if tetrahydro-β-carboline-derived employed protocol, retro-Mannich should avoided due existence two methylene groups between indole nitrogen atom. As consequence, interesting indolenine-fused 2 might afforded major 1b). Herein, report derivatives. Scheme design plan study. Results Our study commenced with evaluation using tetrahydro-β-carboline derivative 1a substrate system consisting iridium precursor [2 mole percent (mol %)] phosphoramidite ligand (4 mol %) tetrahydrofuran (THF) at 50 °C (Table 1).55–85 First, influence ( L1–L8) considered Cs2CO3 (100 base (entries 1–8). L1)86 occurred smoothly (entry 1), delivering product 2a yield (74%) moderate dr value (5.2/1). both diasteroisomers enantiopurity (95% generated L2 Alexakis L3),87 respectively, lead comparable diasteroisomers. dropped slightly 3). addition, Me-THQphos L4) BHPphos L5) developed less terms 4 5). Further more L6–L8) only gave poor 6–8). order improve reaction, bases including DBU, K3PO4, K2CO3, KOAc, NaOAc tested 9–13). found best choice concerning (74%), (7.9/1 ee isomer 96% minor isomer) 13). When no used, completed even after 48 h 14). Inspired work Hartwig co-workers,88 effect counteranion complex examined adding silver salts AgOAc, AgSO3Me, AgOTf, AgBF4 15–18). To delight, all cases, single diastereoisomer. Of particular note, absence base, AgOAc give almost same results 19), while AgSO3Me just 20). Finally, optimal determined described entry 19, where desired isolated 86% ee. Table Optimization Conditionsa Entry L Base Time (h) Yield (%)b drc (major) (%)d (minor) L1 3 74 5.2/1 95 82 4.4/1 94 L3 76 2.9/1 97 4e L4 14 24 8.8/1 / 5e L5 18 5.0/1 6 L6 1.4/1 96 99 7 L7 19 >99 8 L8 42 28 3.0/1 89 85 9 DBU 73 93 10 K3PO4 80 5.4/1 11 K2CO3 6.0/1 12 KOAc 4.5/1 13 7.9/1 23 4.0/1 15f 16g 17h 68 71 18i 83 19/1 91 19f (86j) 20g 6.7/1 Notes: aReaction conditions: (0.2 mmol), (2 %), (2.0 mL) °C. Catalyst prepared nPrNH2 activation.60bCombined diastereoisomers proton nuclear magnetic resonance (1H NMR) analysis CH2Br2 (0.1 mmol) internal standard. cDetermined 1H NMR crude mixtures. dDetermined high-performance liquid chromatography (HPLC) stationary phase. eIn refluxing dioxane. fWith (8 %). gWith hWith AgOTf iWith jIsolated yield. Under optimized conditions, tethered explored examine generality 2). Substrates bearing varied 4-, 5-, 6-position moiety proceed their corresponding yields, diastereo- 2a–2l, 68%–92% 14/1 dr, 88%–96% values lower when seven-substituted indole-derived substrates used 2m, 72% yield, 6/1 95% ee; 2n, 16/1 88% electronic property does show notable influence. either electron-withdrawing (F Cl) electron-donating (Me, MeO, BnO) well tolerated. Moreover, tryptophan-derived substrates, which contain one center ring, underwent smoothly, affording 2o–2q, 91%–96% 8/1 dr). relatively 2q probably caused mismatch R configuration 1q (S,S,Sa)- transition state. gem-dimethyl carboline 2r combined (94%) (>99% [major isomer] 99% [minor isomer]), (1.8/1 carbonate skipped (m = 2), target proceeded well. diastereomeric ratios despite high enantiomeric purity 2s, 71% 94% isomer], 1.1/1 dr; 2t, 69% 1.5/1 stereochemistry 2p (4R,4aR,11S) (4R,4aR,11R) established Overhauser enhancement spectroscopy X-ray crystallographic analysis, respectively.89 absolute other (major isomers) assigned analogy. Substrate scope. activation.60 Combined reported. analysis. Enantiomeric excess (ee) generally exhibit 20/1 It known catalyst Feringa-type control position. utilized, Si-face position allowed attacked. it facial selectivity prochiral nucleophile determines obtained. At stage, calculations90 (M06-2X/SDD/6-31G**) shed some light selectivity. formation selected Two states, TS-2a-( Si ) Re ), leading (4R,4aR) (4R,4aS) 2a, located calculated Gibbs free energy than 1.2 kcal/mol, agreement experimental results. structure relative positively charged allyl electron-rich –synclinal [defined dihedral angle D (Ca–Cb–Cc–Cd), below]. favorable interaction overlapped parts exist help stabilize On hand, antiperiplanar conformation, thus, stabilization expected structure. believe inherent preference 2a.91 noted, strength weak nonbonding sensitive external perturbations. reasonable different solvents counter anions Ir-catalyst employed. Optimized structures Si, Si) Re) (in kcal/mol). (a) (b) side views; (c) (d) Newman projection along forming Cb–Cc bond. associated Ir omitted clarity. green pink, respectively. additional introduced certain positions significantly 2r, 1.8/1 Similar computational investigations applied models. shown 4, difference competitive states TS-2r-( isomers reduced 0.8 kcal/mol. geometric similar ). (–synclinal) (antiperiplanar). causes stronger steric repulsion formal case, exemplified closer hydrogen atom pairs (B[H1⋯H4] 2.15 Å, B(H3⋯H4) 2.09 B[H5⋯H6] 2.10 Å) compared (B[H2⋯H4] 2.37 B[H3⋯H4] 2.16 2.06 Å). brought about overlap diminished energetic gap reduces. situation elongated tether very For state TS-2s'-( keep (–synclinal), strain must suffered bridged cyclic conformation require strong strain.92 minimized 0.3 5 short, qualitatively reproduced trend observed three kinds largely originates beneficial states. will lowered stabilizing neutralized operating Synthetic applications demonstrate utility newly gram-scale carried out. standard 1p 3.76 mmol scale 76% (0.85 g) Gram-scale herein readily transformations Subjecting Pd/C-catalyzed hydrogenation 87% dr. Reduction sodium cyanoborohydride furnished 77% meantime, imine easily converted enamine reacting methyl chloroformate. Transformations products. 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Language: Английский

Catalytic Asymmetric Dearomatization by Transition-Metal Catalysis: A Method for Transformations of Aromatic Compounds DOI Creative Commons
Chao Zheng, Shu‐Li You

Chem, Journal Year: 2016, Volume and Issue: 1(6), P. 830 - 857

Published: Dec. 1, 2016

Language: Английский

Citations

507

Catalytic asymmetric dearomatization (CADA) reaction-enabled total synthesis of indole-based natural products DOI
Chao Zheng, Shu‐Li You

Natural Product Reports, Journal Year: 2019, Volume and Issue: 36(11), P. 1589 - 1605

Published: Jan. 1, 2019

The recent enantioselective total syntheses of natural products enabled by catalytic asymmetric dearomatization reactions indole derivatives are presented.

Language: Английский

Citations

310

Enantioselective Synthesis of Pyrroloindolines via Noncovalent Stabilization of Indole Radical Cations and Applications to the Synthesis of Alkaloid Natural Products DOI
Emily C. Gentry,

Lydia J. Rono,

Martina E. Hale

et al.

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(9), P. 3394 - 3402

Published: Feb. 12, 2018

While interest in the synthetic chemistry of radical cations continues to grow, controlling enantioselectivity reactions these intermediates remains a challenge. Based on recent insights into oxidation tryptophan enzymatic systems, we report photocatalytic method for generation indole as hydrogen-bonded adducts with chiral phosphate anions. These noncovalent open-shell complexes can be intercepted by stable nitroxyl TEMPO· form alkoxyamine-substituted pyrroloindolines high levels enantioselectivity. Further elaboration optically enriched achieved via catalytic single-electron oxidation/mesolytic cleavage sequence furnish transient carbocation that may wide range nucleophiles. Taken together, this two-step provides simple access substituted enantioenriched standard experimental protocol from common intermediate. The design, development, mechanistic study, and scope process are presented, applications synthesis several dimeric pyrroloindoline natural products.

Language: Английский

Citations

217

Further Developments and Applications of Oxazoline-Containing Ligands in Asymmetric Catalysis DOI Creative Commons
Robert Connon,

Brendan Roche,

Balaji V. Rokade

et al.

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(11), P. 6373 - 6521

Published: May 21, 2021

The chiral oxazoline motif is present in many ligands that have been extensively applied a series of important metal-catalyzed enantioselective reactions. This Review aims to provide comprehensive overview the most significant applications oxazoline-containing reported literature starting from 2009 until end 2018. are classified not by reaction which their metal complexes but nature denticity, chirality, and donor atoms involved. As result, continued development ligand architectural design mono(oxazolines), bis(oxazolines), tris(oxazolines) tetra(oxazolines) variations thereof can be more easily monitored reader. In addition, key transition states selected asymmetric transformations will given illustrate features give rise high levels induction. further aid reader, we summarize majority schemes with representative examples highlight variation % yields ees for carefully substrates. should particular interest experts field also serve as useful point new researchers this area. It hoped stimulate both development/design novel transformations.

Language: Английский

Citations

135

Cascade asymmetric dearomative cyclization reactions via transition-metal-catalysis DOI
Yang‐Zi Liu, Hao Song, Chao Zheng

et al.

Nature Synthesis, Journal Year: 2022, Volume and Issue: 1(3), P. 203 - 216

Published: March 14, 2022

Language: Английский

Citations

78

Highly Enantioselective Copper- and Iron-Catalyzed Intramolecular Cyclopropanation of Indoles DOI
Huan Xu,

Yi‐Pan Li,

Yan Cai

et al.

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(23), P. 7697 - 7700

Published: May 26, 2017

We report the first intramolecular enantioselective cyclopropanation of indoles, which was accomplished in good to high yield (up 94%) with excellent enantioselectivity >99.9% ee) by using copper or iron complexes chiral spiro bisoxazolines as catalysts. This reaction is a straightforward, efficient method for constructing polycyclic compounds an all-carbon quaternary stereogenic center at 3-position indole skeleton, core structure shared numerous natural products and bioactive compounds.

Language: Английский

Citations

123

Enantioselective Dearomative [3+2] Cycloaddition Reactions of Benzothiazoles DOI
Dong‐Chao Wang, Ming‐Sheng Xie, Hai‐Ming Guo

et al.

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(45), P. 14111 - 14115

Published: Oct. 10, 2016

Abstract A highly enantioselective dearomative [3+2] cycloaddition of benzothiazole has been successfully developed. wide range benzothiazoles and cyclopropane‐1,1‐dicarboxylates are suitable substrates for this reaction. The desired hydropyrrolo[2,1‐b]thiazole compounds were obtained in excellent enantioselectivity yields (up to 97 % ee yield). With the same catalytic system, a efficient kinetic resolution 2‐substituted was also realized.

Language: Английский

Citations

106

Palladium(0)-Catalyzed Dearomative [3 + 2] Cycloaddition of 3-Nitroindoles with Vinylcyclopropanes: An Entry to Stereodefined 2,3-Fused Cyclopentannulated Indoline Derivatives DOI

Maxime Laugeois,

Johanne Ling,

Charlène Férard

et al.

Organic Letters, Journal Year: 2017, Volume and Issue: 19(9), P. 2266 - 2269

Published: April 18, 2017

The palladium(0)-catalyzed diastereoselective dearomative cyclopentannulation of 3-nitroindoles with vinylcyclopropanes is described. This straightforward and highly atom-economical method leads to a wide range functionalized indolines in good yields diastereoselectivities represents an unprecedented entry toward the valuable 2,3-fused cyclopentannulated indoline scaffold.

Language: Английский

Citations

102

The Diastereoselective Synthesis of Pyrroloindolines by Pd-Catalyzed Dearomative Cycloaddition of 1-Tosyl-2-vinylaziridine to 3-Nitroindoles DOI
Daniel J. Rivinoja, Yi Sing Gee, Michael G. Gardiner

et al.

ACS Catalysis, Journal Year: 2016, Volume and Issue: 7(2), P. 1053 - 1056

Published: Dec. 27, 2016

An efficient, diastereoselective synthesis of densely functionalized pyrroloindolines is reported. The reaction proceeds via cycloaddition a vinylaziridine-derived Pd-stabilized 1,3-dipole to electron-deficient 3-nitroindoles. reactions give the trans diastereoisomer with high selectivity; however, when 4-substituent present on indole ring, reversal diastereoselectivity observed.

Language: Английский

Citations

99

Pd-Catalyzed Asymmetric Dearomative Cycloaddition for Construction of Optically Active Pyrroloindoline and Cyclopentaindoline Derivatives: Access to 3a-Aminopyrroloindolines DOI
Jun‐Qi Zhang, Feifei Tong, Bingbing Sun

et al.

The Journal of Organic Chemistry, Journal Year: 2018, Volume and Issue: 83(5), P. 2882 - 2891

Published: Feb. 19, 2018

Asymmetric dearomative [3 + 2] cycloaddition reactions of 3-nitroindoles with vinyl aziridine and cyclopropanes have been respectively successfully developed in the presence a chiral box/Pd(0) complex. A series enantiomerically enriched 3a-nitro-hexahydropyrrolo[2,3-b]indole 8b-nitrohexahydrocyclopenta[b]indole derivatives containing three contiguous centers are smoothly obtained high yields satisfactory regio-, chemo-, enantioselectivity. Remarkably, synthetic utility this process was demonstrated through direct reductive amination functionalization carbon–carbon double bond desired products.

Language: Английский

Citations

91