Highly Enantioselective Trapping of Carboxylic Oxonium Ylides with Imines for Direct Assembly of Enantioenriched γ-Butenolides

Open AccessCCS ChemistryRESEARCH ARTICLE1 Aug 2020Highly Enantioselective Trapping of Carboxylic Oxonium Ylides with Imines for Direct Assembly of Enantioenriched γ-Butenolides Dan Zhang, Xin Wang, Mengchu Zhang, Zhenghui Kang, Guolan Xiao, Xinfang Xu and Wenhao Hu Dan Zhang Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author , Xin Wang Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author , Mengchu Zhang Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author , Zhenghui Kang Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author , Guolan Xiao Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author , Xinfang Xu *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author and Wenhao Hu *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006 Google Scholar More articles by this author https://doi.org/10.31635/ccschem.020.201900089 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Enantioenriched γ-butenolides are valuable structural cores in many pharmaceuticals and natural products, but their direct and catalytically asymmetric assembly remains rare. Here, we report an efficient, atom-economic synthetic strategy for enantioenriched γ-butenolides via a unique enantioselective reaction of cyclopropene carboxylic acids with imines under the synergistic catalysis of Rh2(esp)2/chiral Brønsted acid system. The reaction involved trapping of carboxylic oxonium ylides, generated from cyclopropene carboxylic acids, which presented as the first asymmetric trapping reactive intermediate in the process. Subsequently, enantioenriched γ-butenolide derivatives were obtained in good-to-high yields (55–94%) with excellent stereoselectivities (up to >95∶5 dr and up to 98∶2 er) under mild conditions. Download figure Download PowerPoint Introduction Butenolides, especially in their enantiomerically pure form, are frequently occurring structural cores of tens of pharmaceuticals and over 13,000 natural products that display a broad range of biological activities.1–6 A recent analysis on the use of butenolides in U.S. Food and Drug Administration (FDA)-approved drugs revealed that these compounds appeared in eight drugs, and their hydrogenated forms (γ-butyrolactones) were present in 10 pharmaceuticals.7 Some representative members of this butenolide family of complexes are listed in Figure 1a. Moreover, the optically active butenolide synthon is a valuable architectural platform for the asymmetric synthesis of diverse pharmacologically active molecules and complex compounds.8,9 Therefore, multiple methods have been developed for the preparation of enantioenriched γ-butenolides over decades.1 The current methodologies usually rely on the derivatization of preformed butenolides with electrophiles at the γ-carbon (Figure 1b).10–13 Thus, a direct and atom-efficient strategy of the de novo construction of catalytic asymmetric architectures of these molecules through a one-step reaction from simple precursors would be highly desirable.14 Since we are focusing on the field of asymmetric interception of reactive intermediates,15,16 we envisioned that an enantioselective trapping strategy of transient cyclic carboxylic oxonium ylides with an electrophile could be applied to construct enantioenriched γ-butenolides (Figure 1c). Figure 1 | Protocols for the synthesis of the enantioenriched γ-butenolides. (a) Pharmaceuticals and natural products containing γ-butenolide cores. (b) General strategy via derivatization of performed butenolides. (c) De novo strategy via trapping of cyclic oxonium ylides. Download figure Download PowerPoint Nonetheless, we considered that the intrinsic instability of carboxylic oxonium ylides might be a major challenge for this proposal. In previous studies, we demonstrated that the transient ammonium/oxonium ylide intermediates formed from carbenes and protic amino groups/hydroxyl groups could be intercepted by electrophiles via nucleophilic addition.17–20 Consequently, we installed an adjacent carbonyl functionality to the metal carbenes to facilitate the trapping process. This introduced carbonyl group is considered essential because studies have relied heavily on the use of α-diazocarbonyl compounds to generate ylides that possess α-carbonyl groups, which could be transformed into more stable enolate or enol intermediates to facilitate trappings and enantiocontrol (Scheme 1a).20–22 Nevertheless, the strategies developed for trapping of ammonium/oxonium ylides rarely work for carboxylic oxonium ylides generated from carboxylic acids and metal carbenes, probably because the higher acidity of carboxylic acids might compromise the stability of these intermediates,23 making the trapping and the stereocontrol more challenging.24 Given the problem regarding trapping of carboxylic oxonium ylides, our first target was to address how to generate the proposed cyclic carboxylic oxonium ylides and enhance their stability. Recently, we uncovered a unique reaction of cyclopropene alcohols with isatins, in which the oxonium ylides from cyclopropene alcohols were captured as reactive ketones at the vinylogous site (Scheme 1b).25 This seminal discovery demonstrated that cyclopropene, a versatile precursor of donor-type vinyl carbenes, could be applied to ylide-trapping chemistry. Inspired by this study and the transition-metal-catalyzed cycloisomerization of cyclopropene carboxylic acids by Komendantov and Dominin,26 we anticipated that the we could employ the stable, readily available cyclopropene carboxylic acids27 to serve as new types of precursors of cyclic carboxylic oxonium ylides. We hypothesized that the transition-metal-catalyzed ring-opening/intramolecular addition of the cyclopropene-containing carboxylic acids would result in cyclic vinyl carboxylic oxonium ylide intermediates (Scheme 1c), in which the conjugated C=C functionality and the hydroxyl group might stabilize the intermediates, enabling efficient capture by an electrophile. Furthermore, using a chiral catalyst to activate the electrophile might result in an enantioenriched transformation.16 However, due to the structural difference between this new intermediate and previously proposed ylides, the reactivity and the regioselectivity of nucleophilic addition to electrophiles remained unknown. Herein, we report a unique reaction of cyclopropene carboxylic acids with imines for the efficient enantioselective synthesis of valuable chiral γ-butenolides. This study has achieved a significant progress in enantioselective interception of carboxylic oxonium ylides and asymmetric electrophilic trapping of reactive ylides from non-α-carbonyl carbenes. Scheme 1 | Trapping of reactive onium ylides intermediates with electrophiles. Download figure Download PowerPoint Experimental Methods The general procedures for enantioselective reaction of cyclopropene carboxylic acids with imines are as follows: The chelating dirhodium(II) catalyst [Rh2(esp)2; 6.0 mg, 0.008 mmol, 4 mol%]; chiral phosphoric acid 4f (12.7 mg, 0.02 mmol, 0.1 eq); 1 (0.36 mmol, 1.8 eq.); and 2 (0.2 mmol, 1.0 eq.) were added to an oven-dried test tube, and tetrahydrofuran (THF; 2.5 mL) was then added. The test tube was capped with a septum and stirred at 25 °C until completion of the reaction (∼ 96 h), as monitored by TLC. Then the reaction mixture was concentrated to obtain the residual crude product of butenolide derivative. The crude preparation was characterized by proton nuclear magnetic resonance (1H NMR) spectroscopy for the determination of diastereoselectivity, and chiral high-performance liquid chromatography (HPLC), for the measurement of the enantiomeric excess (ee). Subsequently, the crude products were purified by column chromatography (silica gel; eluents: 0–30% of EtOAc/petroleum ether) to obtain the afforded pure products 3. More details and characterization of products are available in Supporting Information. Results and Discussion Our study commenced with the reaction of cyclopropene carboxylic acid 1a and imine 2a in the presence of 2 mol% Rh2(esp)2 and 10 mol% 1,1′-Bi-2-naphthol (BINOL)-derived chiral phosphoric acid 4 in dichloromethane (CH2Cl2) (Table 1). To our delight, the reaction gave butenolide derivative 3a in good yields (66–85%) with good diastereomeric ratio (dr) up to 91∶9 and ee values ranging from 6% to 75%. The formation of compound 4e resulted in the highest ee value of 75% (entries 1–9; See the Supporting Information Table S1). Solvent screening using 4e as the chiral source (entries 10–14) revealed that using THF as a solvent could enhance the ee to 86% (entry 12), although an extension of the reaction time was required (CH2Cl2 = 24 h vs THF = 96 h). During the optimization, we found that phosphoric acids with less bulky substituents at the 3,3′-positions ( 4e and 4f) led to higher ee values ( Supporting Information Table S1); hence, reactions under the catalysis of 4f in THF were conducted, affording an improved ee of 91% (90% yield with 90∶10 dr; entry 15). Moreover, lowering the temperature to 0 °C slowed down the reaction remarkably, affording <5% yield (entry 16). Therefore, the reaction conditions determined to be optimum are those shown in entry 15. Table 1 | Optimizations of the Reaction Conditions.a Entry 4 Solvent Yield/%b drc ee/%d 1 4a CH2Cl2 70 82∶18 13 2 4b CH2Cl2 81 85∶15 6 3 4c CH2Cl2 66 90∶10 −6 4 4d CH2Cl2 80 90∶10 42 5 4e CH2Cl2 76 90∶10 75 6 4f CH2Cl2 78 91∶9 67 7 4g CH2Cl2 85 91∶9 57 8 4h CH2Cl2 79 85∶15 50 9 4i CH2Cl2 67 85∶15 48 10 4e CHCl3 83 93∶7 67 11 4e (CH2Cl)2 85 89∶11 61 12 4e THF 60 93∶7 86 13 4e Toluene 71 92∶8 82 14 4e AcOEt 71 89∶11 74 15e 4f THF 92 (90f) 90∶10 91 16g 4f THF <5 / / aReaction conditions: 1a (0.36 mmol), 2a (0.2 mmol), Rh2(esp)2 (2.0 mol%), 4 (10 mol%), solvent (1.5 mL), 24–96 h depending on the solvents. No inert atmosphere was required. bDetermined by 1H NMR analysis of the crude products using 1,3,5-trimethoxylbenzene as the internal standard. cDetermined by 1H NMR analysis of the crude products. dDetermined by HPLC analysis using a chiral stationary phase. eUsing 4.0 mol% Rh2(esp)2; 96 h. fIsolated yield. gAt 0 °C; very slow reaction. With the optimized conditions in hand, we began to assess the scope of the reaction with respect to the utilization of different imine substrates. Notably, various imines were well tolerated and gave the chiral butenolide derivatives in high yields (Scheme 2, top). Among these findings, imines possessing a halogen atom (Br, Cl, and F) or a strong electron-withdrawing group (EWG; CF3 and NO2) at the para-position of Ar2 resulted in products 3aa– 3ae in comparably high yields (87–92%) and good-to-excellent stereoselectivities (up to 95∶5 dr and 97∶3 er). Furthermore, the excellent enantioselectivities and yields were maintained when the substituents were moved to ortho- or meta-position ( 3af– 3ah) or removed from Ar2 ( 3ai– 3aj). Nevertheless, an electron-donating group (EDG; methyl) reduced both the diastereo- and enantioselectivities ( 3ak, 86∶14 dr, 85∶15 er). For the cases of substrates with substituents at the para-position of Ar3, the reaction proceeded well and provided 3al– 3am in good yields with good dr and ee values. Moreover, imines with substituents on both aryl groups were also tolerated and provided the desired products ( 3an– 3ar) with equally good results (74–92%, up to >95∶5 dr and 97∶3 er). Scheme 2 | Substrate scope for the enantioselective reaction of cyclopropene carboxylic acids with imines. Isolated yields are reported. Download figure Download PowerPoint Next, the scope of cyclopropene carboxylic acid as substrates of the reaction was examined (Scheme 2, bottom). Generally, most of the substrates worked well and afforded the desired products ( 3ba– 3bn) in good-to-high yields (59–92%) with excellent dr (up to >95∶5) and er values (up to 98∶2 er). The cyclopropenes with an EDG on the aryl ring led to slightly higher er values than those with an EWG on the aryl ring. Notably, the cyclopropene derived from isoxepac, an anti-inflammatory agent, was also a suitable substrate, providing access to an isoxepac derivative ( 3bo) in 55% yield with a high degree of enantioselectivity (96∶4 er). To demonstrate the synthetic utility of this reaction (Scheme 3), we synthesized 3be via a gram-scale reaction, achieving 84% yield with 91∶9 dr and 96.5∶3.5 er (98∶2 er after recrystallization). Then 3be was used as an architectural platform for the synthesis of diverse heterocycles. For example, hydrogenation under Pd/C/H2 provided γ-butyrolactone 5 in 91% yield. Subsequently, treating 3be with ethylamine gave dihydropyrrol-2-one 6 with destruction of the chiral center and loss of ee. Besides, cycloaddition28 of 3be to 7 resulted in bicyclic derivative 8 in 92% yield with >95∶5 dr and 98∶2 er. The configurations of 5 and 8 were confirmed by two-dimensional NMR and one-dimensional nuclear Overhauser effect (NOE) experiments via NMR spectroscopy. Scheme 3 | Gram-scale synthesis and transformations of 3be. Reagents and conditions: (a) Pd/C, H2, MeOH, room temperature (RT), 91%, 92∶8 dr, 98∶2 er; (b) EtNH2, MeOH, RT, 67%; (c) TFA (20 mol %), DCM, RT, 1 h, 92%, >95∶5 dr, 98∶2 er. Download figure Download PowerPoint To elucidate the reaction mechanism, a control reaction was conducted using a performed γ-butenolide rather than cyclopropene carboxylic acid (Scheme 4). γ-Butenolide 9 was synthesized and then treated with an imine under the standard conditions, but no corresponding product 3bl was obtained. This result indicated that the reaction did not take place through the addition of 9 to the imine, and thus, the trapping of a transient reactive intermediate was more likely. Scheme 4 | The control reaction involving γ-butenolide 9 and an imine could not give the final product 3bl using dirhodium(II) (Rh2(esp)2/chiral Brønsted acid catalytic system. Download figure Download PowerPoint According to the control reaction, previous research findings on cyclopropenes,29–33 and ylide-trapping process,15–20 we proposed a mechanism for the generation of the chiral butenolide derivatives outlined in Scheme 5. Rh2(esp)2 coordinates to the cyclopropene 1 and promotes the ring-opening reaction to afford vinyl rhodium carbene A. Then, the electrophilic carbene is captured intramolecularly by the tethered nucleophilic group (COOH) at the C3 position to form reactive cyclic carboxylic ylide B.33 Disassociation of rhodium catalyst results in the non-metal-associated C and its more stable resonance structure, 3-aryl-2-hydroxyfuran ( C′), which is trapped by a chiral phosphoric-acid-activated imine via the putative transition state TS to afford chiral butenolide derivatives 3 with the regeneration of the chiral Brønsted acid 4. Scheme 5 | Mechanistic proposal of the steps involved in the generation of the enantioenriched γ-butenolide derivatives utilizing the dirhodium(II) (Rh2(esp)2)/chiral Brønsted acid catalytic system. Download figure Download PowerPoint Conclusion We have developed a direct, atom-efficient synthetic strategy for the fabrication of enantioenriched γ-butenolide via an enantioselective reaction of cyclopropene carboxylic acids and imines under synergistic Rh2(esp)2/chiral Brønsted acid catalysis. By developing a nondiazo approach, transient cyclic carboxylic oxonium ylides were formed intramolecularly from cyclopropene carboxylic acids and then trapped by chiral phosphoric-acid-activated imines to provide an efficient access for the generation of valuable butenolides in good-to-high yields (55–94%), generally, with excellent diastereo- and enantioselectivities (up to >95∶5 dr and up to 98∶2 er) under very mild reaction conditions. This is the first created scheme of asymmetric trapping of extremely reactive carboxylic oxonium ylides, as well as the first highly enantioselective trapping of transient ylides without α-carbonyl functionality. Furthermore, we have demonstrated that the stable, readily accessible cyclopropene acid is a powerful source of functionalized donor-type vinyl carbenes that are, otherwise, difficult to obtain from diazo reagents, and prove their efficiency in electrophilic trapping of reactive ylide intermediates, which should inspire new additional transformations. Supporting Information Supplemental Information is available. Conflict of Interest The authors declare no competing interests Acknowledgments This work was supported by National Natural Science Foundation of China (no. 21901259), Guangdong Basic and Applied Basic Research Foundation (no. 2020A1515011116), the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (no. 2016ZT06Y337), and the National Science & Technology Major Project “Key New Drug Creation and Manufacturing Program” of China (no. 2018ZX09711002-006). References 1. Mao B.; Fañanás-Mastral M.; Feringa B. L.Catalytic Asymmetric Synthesis of Butenolides and Butyrolactones.Chem. Rev.2017, 117, 10502–10566. Google Scholar 2. Kitson R. R. A.; Millemaggi A.; Taylor R. J. K.The Renaissance of α-Methylene-γ-Butyrolactones: New Synthetic Approaches.Angew. Chem. Int. Ed.2009, 48, 9426–9451. Google Scholar 3. Roethle P. A.; Trauner D.The Chemistry of Marine Furanocembranoids, Pseudopteranes, Gersolanes, and Related Natural Products.Nat. Prod. Rep.2008, 25, 298–317. Google Scholar 4. Brown S. P.; Goodwin N. C.; MacMillan D. W. C.The First Enantioselective Organocatalytic Mukaiyama–Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture.J. Am. Chem. Soc.2003, 125, 1192–1194. Google Scholar 5. Kitania S.; Miyamotoa K. T.; Takamatsub S.; Herawatia E.; Iguchia H.; Nishitomia K.; Uchidac M.; Nagamitsuc T.; Omurad S.; Ikedab H.; Nihira T.Avenolide, A Streptomyces Hormone Controlling Antibiotic Production in Streptomyces Avermitilis.Proc. Natl. Acad. Sci. USA2011, 108, 16410–16415. Google Scholar 6. Prassas I.; Diamandis E. P.Novel Therapeutic Applications of Cardiac Glycosides.Nat. Rev. Drug Discov.2008, 7, 926–935. Google Scholar 7. Delost M. D.; Smith D. T.; Anderson B. J.; Njardarson J. T.From Oxiranes to Oligomers: Architectures of U.S. FDA Approved Pharmaceuticals Containing Oxygen Heterocycles.J. Med. Chem.2018, 61, 10996–11020. Google Scholar 8. Qin T.; Johnson R. P.; Porco J. A.Vinylogous Addition of Siloxyfurans to Benzopyryliums: A Concise Approach to the Tetrahydroxanthone Natural Products.J. Am. Chem. Soc.2011, 133, 1714–1717. Google Scholar 9. Evans D. A.; Dunn T. B.; Kværnø L.; Beauchemin A.; Raymer B.; Olhava E. J.; Mulder J. A.; Juhl M.; Kagechika K.; Favor D. A.Total Synthesis of (+)-Azaspiracid-1. Part II: Synthesis of the EFGHI Sulfone and Completion of the Synthesis.Angew. Chem. Int. Ed.2007, 46, 4698–4703. Google Scholar 10. Pansare S. V.; Paul E. K.The Organocatalytic Vinylogous Aldol Reaction: Recent Advances.Chem. Eur. J.2011, 17, 8770–8779. Google Scholar 11. Kitajima H.; Ito K.; Katsuki T.A New Methodology for the Stereoselective Synthesis of 4-Substituted Butenolides: Asymmetric Michael Addition Reaction of 2-(Trimethylsilyloxy)furans to Oxazolidinone Enoates.Tetrahedron1997, 53, 17015–17028. Google Scholar 12. Carswell E. L.; Snapper M. L.; Hoveyda A. H.A Highly Efficient and Practical Method for Catalytic Asymmetric Vinylogous Mannich (AVM) Reactions.Angew. Chem. Int. Ed.2006, 45, 7230–7233. Google Scholar 13. Yan L.; Wu X.; Liu H.; Xie L.; Jiang Z.Catalytic Asymmetric Synthesis of γ-Butenolides by Direct Vinylogous Reactions.Mini-Rev. Med. Chem.2013, 13, 845–853. Google Scholar 14. Kawamata Y.; Hashimoto T.; Maruoka K.A Chiral Electrophilic Selenium Catalyst for Highly Enantioselective Oxidative Cyclization.J. Am. Chem. Soc.2016, 138, 5206–5209. Google Scholar 15. Guo X.; Hu W.Novel Multicomponent Reactions via Trapping of Protic Onium Ylides with Electrophiles.Acc. Chem. Res.2013, 46, 2427–2440. Google Scholar 16. Zhang D.; Hu W.Asymmetric Multicomponent Reactions Based on Trapping of Active Intermediates.Chem. Rec.2017, 17, 739–753. Google Scholar 17. Wang Y.; Zhu Y.; Chen Z.; Mi A.; Hu W.; Doyle M. P.A Novel Three-Component Reaction Catalyzed by Dirhodium(II) Acetate: Decomposition of Phenyldiazoacetate with Arylamine and Imine for Highly Diastereoselective Synthesis of 1,2-Diamines.Org. Lett.2003, 5, 3923–3926. Google Scholar 18. Lu C.-D.; Liu H.; Chen Z.-Y.; Hu W.-H.; Mi A.-Q.Three-Component Reaction of Aryl Diazoacetates, Alcohols, and Aldehydes (or imines): Evidence of Alcoholic Oxonium Ylide Intermediates.Org. Lett.2005, 7, 83–86. Google Scholar 19. Zhang D.; Zhou J.; Xia F.; Kang Z.; Hu W.Bond Cleavage, Fragment Modification and Reassembly in Enantioselective Three-Component Reactions.Nat. Commun.2015, 6, 5801. Google Scholar 20. Kang Z.; Wang Y.; Zhang D.; Wu R.; Xu X.; Hu W.Asymmetric Counter-Anion-Directed Aminomethylation: Synthesis of Chiral β-Amino Acids via Trapping of An Enol Intermediate.J. Am. Chem. Soc.2019, 141, 1473–1478. Google Scholar 21. Liang Y.; Zhou H.; Yu Z.-X.Why is Copper(I) Complex More Competent than Dirhodium(II) Complex in Catalytic Asymmetric O–H Insertion Reactions? A Computational Study of the Metal Carbenoid O–H Insertion Into Water.J. Am. Chem. Soc.2009, 131, 17783–17785. Google Scholar 22. Ren Y.-Y.; Zhu S.-F.; Zhou Q.-L.Chiral Proton-Transfer Shuttle Catalysts for Carbene Insertion Reactions.Org. Biomol. Chem.2018, 16, 3087–3094. Google Scholar 23. Tan F.; Liu X.; Hao X.; Tang Y.; Lin L.; Feng X.Asymmetric Catalytic Insertion of α-Diazo Carbonyl Compounds into O–H Bonds of Carboxylic Acids.ACS Catal.2016, 6, 6930–6934. Google Scholar 24. Zhai C.; Xing D.; Qian Y.; Ji J.; Ma C.; Hu W.Trapping of Carboxylic Oxonium Ylides with N-Boc Imines for the Facile Synthesis of β-Amino Alcohol Derivatives.Synlett2014, 25, 1745–1750. Google Scholar 25. Zhang D.; Kang Z.; Liu J.; Hu W.Metal-Dependent Umpolung Reactivity of Carbenes Derived from Cyclopropenes.iScience2019, 14, 292–300. Google Scholar 26. Rao Y. S.Recent Advances in the Chemistry of Unsaturated Lactones.Chem. Rev.1976, 76, 625–694. See the ref. 565 therein. Google Scholar 27. Liao L.; Yan N.; Fox J. M.Dianion Approach to Chiral Cyclopropene Carboxylic Acids.Org. Lett.2004, 6, 4937–4939. Google Scholar 28. Chen P.; Chen Z.-C.; Li Y.; Ouyang Q.; Du W.; Chen Y.-C.Auto-Tandem Cooperative Catalysis Using Phosphine/Palladium: Reaction of Morita–Baylis–Hillman Carbonates and Allylic Alcohols.Angew. Chem. Int. Ed.2019, 58, 4036–4040. Google Scholar 29. Archambeau A.; Miege F.; Meyer C.; Cossy J.Intramolecular Cyclopropanation and C–H Insertion Reactions with Metal Carbenoids Generated from Cyclopropenes.Acc. Chem. Res.2015, 48, 1021–1031. Google Scholar 30. Vicente R.Recent Progresses Towards the Strengthening of Cyclopropene Chemistry.Synthesis2016, 48, 2343–2360. Google Scholar 31. Zhang H.; Wang K.; Wang B.; Yi H.; Hu F.; Li C.; Zhang Y.; Wang J.Rhodium(III)-Catalyzed Transannulation of Cyclopropenes with N-Phenoxyacetamides through C–H Activation.Angew. Chem. Int. Ed.2014, 53, 13234–13238. Google Scholar 32. Wang B.; Yi H.; Zhang H.; Sun T.; Zhang Y.; Wang J.Ru(II)-Catalyzed Cross-Coupling of Cyclopropenes with Diazo Compounds: Formation of Olefins from Two Different Carbene Precursors.J.Org. Chem.2018, 83, 1026–1032. Google Scholar 33. Chen J.; Ma S.Catalyst-Controlled Ring-Opening Cycloisomerization Reactions of Cyclopropenyl Carboxylates for Highly Regioselective Synthesis of Different 2-Alkoxyfurans.Chem. Asian J.2010, 5, 2415–2421. Google Scholar Previous articleNext article FiguresReferencesRelatedDetailsCited ByLv X, Liu S, Zhou S, Dong G, Xing D, Xu X and Hu W (2020) Asymmetric Three-Component Propargyloxylation for Direct Assembly of Polyfunctionalized Chiral Succinate Derivatives, CCS Chemistry, 3:7, (1903-1912), Online publication date: 1-Jul-2021. Issue AssignmentVolume 2Issue 4Page: 432-439Supporting Information Copyright & Permissions© 2020 Chinese Chemical SocietyKeywordsγ-butenolidesvinyl carbenesylidescyclopropenesasymmetric catalysisAcknowledgmentsThis work was supported by National Natural Science Foundation of China (no. 21901259), Guangdong Basic and Applied Basic Research Foundation (no. 2020A1515011116), the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (no. 2016ZT06Y337), and the National Science & Technology Major Project “Key New Drug Creation and Manufacturing Program” of China (no. 2018ZX09711002-006). Downloaded 2,344 times PDF DownloadLoading ...