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Mini-Reviews in Organic Chemistry

Editor-in-Chief

ISSN (Print): 1570-193X
ISSN (Online): 1875-6298

Mini-Review Article

Gold-catalyzed Reactions of Substituted 1,5-diynes: Recent Advances and their Chemistry

Author(s): Perla Bharath Kumar, Kongara Damodar and Kanaparthy Suneel*

Volume 21, Issue 4, 2024

Published on: 08 May, 2023

Page: [424 - 435] Pages: 12

DOI: 10.2174/1570193X20666230302114722

Price: $65

Abstract

Diynes are identified as exceptionally potent and superior substrates in gold-catalyzed organic transformations. Gold (I) and gold (III) complexes exhibit unique activity towards diynes, encouraging the nucleophilic addition of different functional groups both inter and intra- molecularly. In this review, particularly, we focused on recent advances in gold-catalyzed reactions of 1,5-diynes along with their mechanistic aspects. These reactions are interesting for constructing molecular complexity, medicinal chemistry, and material science.

Graphical Abstract

[1]
(a) Asiri, A.M.; Hashmi, A.S.K. Gold-catalysed reactions of diynes. Chem. Soc. Rev., 2016, 45(16), 4471-4503.
[http://dx.doi.org/10.1039/C6CS00023A] [PMID: 27385433];
(b) Pflästerer, D.; Hashmi, A.S.K. Gold catalysis in total synthesis-Recent achievements. Chem. Soc. Rev., 2016, 45(5), 1331-1367.
[http://dx.doi.org/10.1039/C5CS00721F] [PMID: 26673389];
(c) Ohno, H. gold-catalyzed cascade reactions of alkynes for construction of polycyclic compounds. Isr. J. Chem., 2013, 53(11-12), 869-882.
[http://dx.doi.org/10.1002/ijch.201300054];
(d) Bongers, N.; Krause, N. Golden opportunities in stereoselective catalysis. Angew. Chem. Int. Ed., 2008, 47(12), 2178-2181.
[http://dx.doi.org/10.1002/anie.200704729] [PMID: 18270991];
(e) Fürstner, A.; Davies, P.W. Catalytic carbophilic activation: Catalysis by platinum and gold π acids. Angew. Chem. Int. Ed., 2007, 46(19), 3410-3449.
[http://dx.doi.org/10.1002/anie.200604335] [PMID: 17427893];
(f) Hashmi, A.S.K.; Hutchings, G.J. Gold Catalysis. Angew. Chem. Int. Ed., 2006, 45(47), 7896-7936.
[http://dx.doi.org/10.1002/anie.200602454] [PMID: 17131371];
(g) Hashmi, A.S.K. Homogeneous catalysis by gold. Gold Bull., 2004, 37(1-2), 51-65.
[http://dx.doi.org/10.1007/BF03215517];
(h) Day, D.P.; Chan, P.W.H. Gold‐catalyzed cycloisomerizations of 1, n ‐diyne carbonates and esters. Adv. Synth. Catal., 2016, 358(9), 1368-1384.
[http://dx.doi.org/10.1002/adsc.201600005]
[2]
(a) Nösel, P.; dos Santos Comprido, L.N.; Lauterbach, T.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. 1,6-Carbene transfer: Gold-catalyzed oxidative diyne cyclizations. J. Am. Chem. Soc., 2013, 135(41), 15662-15666.
[http://dx.doi.org/10.1021/ja4085385] [PMID: 24050384];
(b) Bucher, J.; Wurm, T.; Taschinski, S.; Sachs, E.; Ascough, D.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. Dual gold catalysis: Synthesis of Fluorene derivatives from diynes. Adv. Synth. Catal., 2017, 359(2), 225-233.
[http://dx.doi.org/10.1002/adsc.201600987];
(c) Rettenmeier, E.; Hansmann, M.M.; Ahrens, A.; Rübenacker, K.; Saboo, T.; Massholder, J.; Meier, C.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. Insights into the gold-catalyzed propargyl ester rearrangement/tandem cyclization sequence: Radical versus gold catalysis-Myers-saito- versus Schmittel-type cyclization. Chem. Eur. J., 2015, 21(41), 14401-14409.
[http://dx.doi.org/10.1002/chem.201501725] [PMID: 26291466];
(d) Shu, C.; Shi, C.Y.; Sun, Q.; Zhou, B.; Li, T.Y.; He, Q.; Lu, X.; Liu, R.S.; Ye, L.W. Generation of endocyclic vinyl carbene complexes via gold-catalyzed oxidative cyclization of terminal diynes: Toward naphthoquinones and carbazolequinones. ACS Catal., 2019, 9(2), 1019-1025.
[http://dx.doi.org/10.1021/acscatal.8b04455];
(e) Tavakkolifard, S.; Sekine, K.; Reichert, L.; Ebrahimi, M.; Museridz, K.; Michel, E.; Rominger, F.; Babaahmadi, R.; Ariafard, A.; Yates, B.F.; Rudolph, M.; Hashmi, A.S.K. Gold‐catalyzed regiospecific annulation of unsymmetrically substituted 1,5‐diynes for the precise synthesis of bispentalenes. Chem. Eur. J., 2019, 25(52), 12180-12186.
[http://dx.doi.org/10.1002/chem.201902381] [PMID: 31310400];
(f) Wan, Q.; Xin, L.; Zhang, J.; Huang, X. Efficient access to 1,3,4-trisubstituted pyrroles via gold-catalysed cycloisomerization of 1,5-diynes. Org. Biomol. Chem., 2022, 20(8), 1647-1651.
[http://dx.doi.org/10.1039/D1OB02393D] [PMID: 35137761]
[3]
(a) Wurm, T.; Bucher, J.; Duckworth, S.B.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. On the gold-catalyzed generation of vinyl cations from 1,5-diynes. Angew. Chem. Int. Ed., 2017, 56(12), 3364-3368.
[http://dx.doi.org/10.1002/anie.201700057] [PMID: 28194865];
(b) Sekine, K.; Stuck, F.; Schulmeister, J.; Wurm, T.; Zetschok, D.; Rominger, F.; Rudolph, M.; Hashmi, A.S.K. N-heterocycle-fused pentalenes by a gold-catalyzed annulation of diethynyl-quinoxalines and -phenazines. Chem. Eur. J., 2018, 24(48), 12515-12518.
[http://dx.doi.org/10.1002/chem.201803096] [PMID: 29923240];
(c) Hashmi, A.S.K. Gold-catalyzed organic reactions. Chem. Rev., 2007, 107(7), 3180-3211.
[http://dx.doi.org/10.1021/cr000436x] [PMID: 17580975];
(d) Krause, N.; Winter, C. Gold-catalyzed nucleophilic cyclization of functionalized allenes: A powerful access to carbo- and heterocycles. Chem. Rev., 2011, 111(3), 1994-2009.
[http://dx.doi.org/10.1021/cr1004088] [PMID: 21314182];
(e) Arcadi, A. Alternative synthetic methods through new developments in catalysis by gold. Chem. Rev., 2008, 108(8), 3266-3325.
[http://dx.doi.org/10.1021/cr068435d] [PMID: 18651778];
(f) Jiménez-Núñez, E.; Echavarren, A.M. Gold-catalyzed cycloisomerizations of enynes: A mechanistic perspective. Chem. Rev., 2008, 108(8), 3326-3350.
[http://dx.doi.org/10.1021/cr0684319] [PMID: 18636778];
(g) Gorin, D.J.; Toste, F.D. Relativistic effects in homogeneous gold catalysis. Nature, 2007, 446(7134), 395-403.
[http://dx.doi.org/10.1038/nature05592] [PMID: 17377576];
(h) Hashmi, A.S.K. Introduction: Gold Chemistry. Chem. Rev., 2021, 121(14), 8309-8310.
[http://dx.doi.org/10.1021/acs.chemrev.1c00393] [PMID: 34315211];
(i) Witzel, S.; Hashmi, A.S.K.; Xie, J. Light in gold catalysis. Chem. Rev., 2021, 121(14), 8868-8925.
[http://dx.doi.org/10.1021/acs.chemrev.0c00841] [PMID: 33492123];
(j) Jazzar, R.; Soleilhavoup, M.; Bertrand, G. Cyclic (Alkyl)- and (Aryl)-(amino)carbene coinage metal complexes and their applications. Chem. Rev., 2020, 120(9), 4141-4168.
[http://dx.doi.org/10.1021/acs.chemrev.0c00043];
(k) Hendrich, C.M.; Sekine, K.; Koshikawa, T.; Tanaka, K.; Hashmi, A.S.K. Homogeneous and heterogeneous gold catalysis for materials science. Chem. Rev., 2021, 121(14), 9113-9163.
[http://dx.doi.org/10.1021/acs.chemrev.0c00824] [PMID: 33315377];
(l) Hashmi, A.S.K.; Toste, F.D. Modern Gold Catalyzed Synthesis; Wiley-VCH: Weinheim, 2012.
[http://dx.doi.org/ 10.1002/9783527646869];
(m) Toste, F.D.; Michelet, V. Gold Catalysis: An Homogeneous Approach; Imperial College Press: London, 2014.
[http://dx.doi.org/10.1142/p831];
(n) Hopkinson, M.N.; Tlahuext-Aca, A.; Glorius, F. Merging visible light photoredox and gold catalysis. Acc. Chem. Res., 2016, 49(10), 2261-2272.
[http://dx.doi.org/10.1021/acs.accounts.6b00351] [PMID: 27610939];
(o) Nijamudheen, A.; Datta, A. gold‐catalyzed cross‐coupling reactions: An overview of design strategies, mechanistic studies, and applications. Chem. Eur. J., 2020, 26(7), 1442-1487.
[http://dx.doi.org/10.1002/chem.201903377] [PMID: 31657487];
(p) Banerjee, S.; Bhoyare, V.W.; Patil, N.T. Gold and hypervalent iodine(III): Liaisons over a decade for electrophilic functional group transfer reactions. Chem. Commun. (Camb.), 2020, 56(18), 2677-2690.
[http://dx.doi.org/10.1039/D0CC00106F] [PMID: 32090230]
[4]
(a) Gómez-Suárez, A.; Nolan, S.P. Dinuclear gold catalysis: Are two gold centers better than one? Angew. Chem. Int. Ed., 2012, 51(33), 8156-8159.
[http://dx.doi.org/10.1002/anie.201203587] [PMID: 22811398];
(b) Braun, I.; Asiri, A.M.; Hashmi, A.S.K. Gold Catalysis 2.0. ACS Catal., 2013, 3(8), 1902-1907.
[http://dx.doi.org/10.1021/cs400437s];
(c) Hashmi, A.S.K. Dual gold catalysis. Acc. Chem. Res., 2014, 47(3), 864-876.
[http://dx.doi.org/10.1021/ar500015k] [PMID: 24533563];
(d) Hashmi, A.S.K.; Braun, I.; Nösel, P.; Schadlich, J.; Wieteck, M.; Rudolph, M.; Rominger, F. Simple gold-catalyzed synthesis of benzofulvenes-gem-diaurated species as “instant dual-activation” precatalysts. Angew. Chem. Int. Ed., 2014, 51, 4456.
[http://dx.doi.org/10.1002/anie.201109183];
(f) Vachhani, D.D.; Galli, M.; Jacobs, J.; Meervelt, L.V.; vander Eycken, E.V. Synthesis of (spiro)cyclopentapyridin-ones via Csp3–H functionalization: A post-Ugi gold-catalyzed regioselective tandem cyclization. Chem. Commun., 2013, 49, 7171.
[http://dx.doi.org/10.1039/C3CC43418D];
(g) Graf, K.; Hindenberg, P.D.; Tokimizu, Y. The role of acetylides in dual gold catalysis: A mechanistic investigation of the selectivity difference in the naphthalene synthesis from diynes. Chem- CatChem., 2014, 6, 199.
[http://dx.doi.org/10.1002/cctc.201300820];
(h) Hansmann, M.M.; Tsˇupova, S.; Rudolph, M. Gold-catalyzed cyclization of diynes: Controlling the mode of 5-endo versus 6- endo cyclization-an experimental and theoretical study by utilizing diethynylthiophenes. Chem. Eur. J., 2014, 20, 2215.
[http://dx.doi.org/10.1002/chem.201302967];
(i) Vilhelmsen, M.H.; Hashmi, A.S.K. Reaction mechanism for the dual gold-catalyzed synthesis of dibenzopentalene: A DFT Study. Chem. Eur. J., 2014, 20, 1901.
[http://dx.doi.org/10.1002/chem.201303636];
(j) Wieteck, M.; Tokimizu, Y.; Rudolph, M.; Rominger, F. Dual gold catalysis: Synthesis of polycyclic compounds via C-H Insertion of gold vinylidenes. Chem. Eur. J., 2014, 20, 16331.
[http://dx.doi.org/10.1002/chem.201404987];
(k) Larsen, M.H.; Houk, K.N.; Hashmi, A.S.K. Dual Gold Catalysis: Stepwise catalyst transfer via dinuclear clusters. J. Am. Chem. Soc., 2015, 137, 10668.
[http://dx.doi.org/10.1021/jacs.5b05773];
(l) Yu, C.; Chen, B.; Zhou, T. Gold (I)-catalyzed tandem transformation with diynes: Rapid access to linear cyclopentenone-fused polycyclic molecules. Angew. Chem. Int. Ed., 2015, 54, 10903.
[http://dx.doi.org/10.1002/anie.201503599]
[5]
Bucher, J.; Wurm, T.; Nalivela, K.S.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. Cyclization of gold acetylides: Synthesis of vinyl sulfonates via gold vinylidene complexes. Angew. Chem. Int. Ed., 2014, 53(15), 3854-3858.
[http://dx.doi.org/10.1002/anie.201310280]
[6]
(a) Hansmann, M.M.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. Mechanistic switch in dual gold catalysis of diynes: C(sp3)–H activation through bifurcation vinylidene versus carbene pathways. Angew. Chem. Int. Ed.,, 2013, 52(9), 2593-2598.
[http://dx.doi.org/10.1002/anie.201208777];
(c) Hansmann, M.M.; Rominger, F.; Hashmi, A.S.K. Gold–allenylidenes-An experimental and theoretical study. Chem. Sci.(Camb.), 2013, 4(4), 1552.
[http://dx.doi.org/10.1039/c3sc22227f]
[7]
(a) Purnachandar, D.; Suneel, K.; Balasubramanian, S.; Karunakar, G.V. Gold–carbene assisted formation of tetraarylmethane derivatives: Double X–H activation by gold. Org. Biomol. Chem., 2019, 17(19), 4856-4864.
[http://dx.doi.org/10.1039/C9OB00470J] [PMID: 31038501];
(b) Dalovai, P.; Karunakar, G.V.; Damodaran Nadar, V.; Doddi, V.R.; Kanaparthy, S. Gold-catalyzed formation of substituted aminobenzophenone derivatives via intramolecular 6-endo-dig cyclization. J. Chem. Sci., 2021, 133(1), 19.
[http://dx.doi.org/10.1007/s12039-020-01860-8];
(c) Purnachandar, D.; Sreenivasulu, G.; Karunakar, G.V.; Sridhar, B.; Damodaran, V.N.; Suneel, K. AuCl3-catalyzed synthesis of (E/Z)‒chloroallyl carbazoles via a cascade cyclization process. ARKIVOC, 2020, 2020(8), 33-45.
[http://dx.doi.org/10.24820/ark.5550190.p011.303];
(d) Gottam, S.; Gaddam, V.; Kanaparthy, S. Gold-catalyzed reactions using N-propargyl β-enaminones. ARKIVOC, 2022, 2022(8), 1-18.
[http://dx.doi.org/ 10.24820/ark.5550190.p011.796]
[8]
Karunakar, G.V.; Raju, C.E.; Sreenivasulu, G.; Kumar, P.B.; Kadiyala, V.; Sridhar, B.; Kadiyala, V.; Sridhar, B. Cationic gold-catalyzed intramolecular cyclization of substituted 1,5-diynes to access indenone derivatives. Chem. Asian J., 2022, 17(8), e202101408.
[http://dx.doi.org/10.1002/asia.202101408] [PMID: 35243791]
[9]
(a) Swaminathan, S.; Narayanan, K.V. Rupe and meyer-schuster rearrangements. Chem. Rev., 1971, 71(5), 429-438.
[http://dx.doi.org/10.1021/cr60273a001];
(b) Hansmann, M.M.; Hashmi, A.S.K.; Lautens, M. Gold meets rhodium: Tandem one-pot synthesis of β-disubstituted ketones via Meyer-Schuster rearrangement and asymmetric 1,4-addition. Org. Lett., 2013, 15(13), 3226-3229.
[http://dx.doi.org/10.1021/ol4011739] [PMID: 23777565];
(c) Engel, D.A.; Dudley, G.B. The Meyer–Schuster rearrangement for the synthesis of α,β-unsaturated carbonyl compounds. Org. Biomol. Chem., 2009, 7(20), 4149-4158.
[http://dx.doi.org/10.1039/b912099h] [PMID: 19795050];
(d) Pennell, M.N.; Kyle, M.P.; Gibson, S.M.; Male, L.; Turner, P.G.; Grainger, R.S.; Sheppard, T.D. Intercepting the Gold-Catalysed Meyer-Schuster Rearrangement by Controlled Protodemetallation: A regioselective hydration of propargylic alcohols. Adv. Synth. Catal., 2016, 358(9), 1519-1525.
[http://dx.doi.org/10.1002/adsc.201600101] [PMID: 29200990];
(e) Engel, D.A.; Dudley, G.B. Olefination of ketones using a gold(III)-catalyzed Meyer-Schuster rearrangement. Org. Lett., 2006, 8(18), 4027-4029.
[http://dx.doi.org/10.1021/ol0616743] [PMID: 16928065];
(f) Sugawara, Y.; Yamada, W.; Yoshida, S.; Ikeno, T.; Yamada, T. Carbon dioxide-mediated catalytic rearrangement of propargyl alcohols into α,β-unsaturated ketones. J. Am. Chem. Soc., 2007, 129(43), 12902-12903.
[http://dx.doi.org/10.1021/ja074350y] [PMID: 17918841];
(g) Yang, Y.; Hu, W.; Ye, X.; Wang, D.; Shi, X. Preparation of Triazole Gold(III) Complex as an Effective Catalyst for the Synthesis of E ‐α‐Haloenones. Adv. Synth. Catal., 2016, 358(16), 2583-2588.
[http://dx.doi.org/ 10.1002/adsc.201600243];
(h) Zhu, H.; Chen, Z. DDQ-Mediated Oxidative Radical Cycloisomerization of 1,5-Diynols: Regioselective synthesis of benzo[ b]fluorenones under metal-free conditions. Org. Lett., 2016, 18(3), 488-491.
[http://dx.doi.org/10.1021/acs.orglett.5b03533] [PMID: 26815082]
[10]
Kadiyala, V.; Raju, C.E.; Bania, K.K.; Sridhar, B.; Karunakar, G.V. Gold (I)‐Promoted Intermolecular cascade annulation to access 2‐Hydroxybenzocarbazoles via a Meyer–Schuster rearrangement. Chem. Asian J., 2022, 17(3), e202101269.
[http://dx.doi.org/10.1002/asia.202101269] [PMID: 34874100]
[11]
Kadiyala, V.; Bharath Kumar, P.; Balasubramanian, S.; Karunakar, G.V. Gold-catalyzed Synthesis of 6-Hydroxyindoles from alkynylcyclohexadienones and substituted amines. J. Org. Chem., 2019, 84(18), 12228-12236.
[http://dx.doi.org/10.1021/acs.joc.9b02023] [PMID: 31460758]
[12]
Wurm, T.; Bucher, J.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. On the gold-catalyzed Generation of Phenyl Cations from 1,5-Diynes. Adv. Synth. Catal., 2017, 359(10), 1637-1642.
[http://dx.doi.org/10.1002/adsc.201700231]
[13]
Chen, C.C.; Chen, C.M.; Wu, M.J. Transition metal-catalyzed cascade cyclization of aryldiynes to halogenated benzo[b]naphtho[2,1-d]thiophene derivatives. J. Org. Chem., 2014, 79(10), 4704-4711.
[http://dx.doi.org/10.1021/jo500377v] [PMID: 24750047]
[14]
Tokimizu, Y.; Wieteck, M.; Rudolph, M.; Oishi, S.; Fujii, N.; Hashmi, A.S.K.; Ohno, H. Dual gold catalysis: A novel synthesis of bicyclic and tricyclic pyrroles from N-propargyl ynamides. Org. Lett., 2015, 17(3), 604-607.
[http://dx.doi.org/10.1021/ol503623m] [PMID: 25611870]
[15]
Ghosh, N.; Nayak, S.; Sahoo, A.K. Gold(I)-catalyzed 6-endo-dig hydrative cyclization of an alkyne-tethered ynamide: Access to 1,6-dihydropyridin-2(3H)ones. Chem.Eur. J., 2013, 19(29), 9428-9433.
[http://dx.doi.org/10.1002/chem.201301599] [PMID: 23788463]
[16]
Nieto-Oberhuber, C.; López, S.; Echavarren, A.M. Intramolecular [4 + 2] cycloadditions of 1,3-enynes or arylalkynes with alkenes with highly reactive cationic phosphine Au(I) complexes. J. Am. Chem. Soc., 2005, 127(17), 6178-6179.
[http://dx.doi.org/10.1021/ja042257t] [PMID: 15853316]
[17]
Hirano, K.; Inaba, Y.; Takahashi, N.; Shimano, M.; Oishi, S.; Fujii, N.; Ohno, H. Direct synthesis of fused indoles by gold-catalyzed cascade cyclization of diynes. J. Org. Chem., 2011, 76(5), 1212-1227.
[http://dx.doi.org/10.1021/jo102507c] [PMID: 21250725]
[18]
Hou, Q.; Zhang, Z.; Kong, F.; Wang, S.; Wang, H.; Yao, Z.J. Assembly of fused indenes via Au(I)-catalyzed C1–C5 cyclization of enediynes bearing an internal nucleophile. Chem. Commun. (Camb.), 2013, 49(7), 695-697.
[http://dx.doi.org/10.1039/C2CC36245G] [PMID: 23223174]
[19]
Hashmi, A.S.K.; Wieteck, M.; Braun, I.; Nösel, P.; Jongbloed, L.; Rudolph, M.; Rominger, F. Gold-catalyzed synthesis of dibenzopentalenes - Evidence for gold vinylidenes. Adv. Synth. Catal., 2012, 354(4), 555-562.
[http://dx.doi.org/10.1002/adsc.201200086]
[20]
Nösel, P.; Müller, V.; Mader, S.; Moghimi, S.; Rudolph, M.; Braun, I.; Rominger, F.; Hashmi, A.S.K. gold-catalyzed hydroarylating cyclization of 1,2-Bis(2-iodoethynyl)benzenes. Adv. Synth. Catal., 2015, 357(2-3), 500-506.
[http://dx.doi.org/10.1002/adsc.201400749]
[21]
Mamane, V.; Hannen, P.; Fürstner, A. Synthesis of phenanthrenes and polycyclic heteroarenes by transition-metal catalyzed cycloisomerization reactions. Chem.. Eur. J.,, 2004, 10(18), 4556-4575.
[http://dx.doi.org/10.1002/chem.200400220] [PMID: 15378635]
[22]
Hashmi, A.S.K.; Braun, I.; Rudolph, M.; Rominger, F. The role of gold acetylides as a selectivity trigger and the importance of gem -Diaurated species in the gold-catalyzed hydroarylating-aromatization of arene-diynes. Organometallics, 2012, 31(2), 644-661.
[http://dx.doi.org/10.1021/om200946m]
[23]
Hashmi, A.S.K.; Wieteck, M.; Braun, I.; Rudolph, M.; Rominger, F. Gold vinylidene complexes: Intermolecular C(sp3)-H insertions and cyclopropanations pathways. Angew. Chem. Int. Ed., 2012, 51(42), 10633-10637.
[http://dx.doi.org/10.1002/anie.201204015]
[24]
Nösel, P.; Lauterbach, T.; Rudolph, M.; Rominger, F.; Hashmi, A.S.K. Gold-catalyzed synthesis of iodofulvenes. Chem.. Eur. J.,, 2013, 19(26), 8634-8641.
[http://dx.doi.org/10.1002/chem.201300507] [PMID: 23653259]
[25]
Ye, L.; Wang, Y.; Aue, D.H.; Zhang, L. Experimental and computational evidence for gold vinylidenes: Generation from terminal alkynes via a bifurcation pathway and facile C–H insertions. J. Am. Chem. Soc., 2012, 134(1), 31-34.
[http://dx.doi.org/10.1021/ja2091992]

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