- Radical Carbonyl Propargylation by Dual Catalysis
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Carbonyl propargylation has been established as a valuable tool in the realm of carbon–carbon bond forming reactions. The 1,3-enyne moiety has been recognized as an alternative pronucleophile in the above transformation through an ionic mechanism. Herein, we report for the first time, the radical carbonyl propargylation through dual chromium/photoredox catalysis. A library of valuable homopropargylic alcohols bearing all-carbon quaternary centers could be obtained by a catalytic radical three-component coupling of 1,3-enynes, aldehydes and suitable radical precursors (41 examples). This redox-neutral multi-component reaction occurs under very mild conditions and shows high functional group tolerance. Remarkably, bench-stable, non-toxic, and inexpensive CrCl3 could be employed as a chromium source. Preliminary mechanistic investigations suggest a radical-polar crossover mechanism, which offers a complementary and novel approach towards the preparation of valuable synthetic architectures from simple chemicals.
- Huang, Huan-Ming,Bellotti, Peter,Daniliuc, Constantin G.,Glorius, Frank
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supporting information
p. 2464 - 2471
(2020/12/07)
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- Fe-Catalyzed Selective Cyclopropanation of Enynes under Photochemical or Thermal Conditions
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The nucleophilic Fe-complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the cyclopropanation of enynes to substituted propargyl cyclopropanes using diazoesters as carbene surrogates. The catalyst can be activated either thermally in the presence of catalytic amounts of 4-nitroanisole or under photochemical conditions. Cyclopropanation occurs selectively at the enyne moiety; alternative olefinic moieties remain intact.
- Picher, Marie-Idrissa,Plietker, Bernd
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supporting information
p. 340 - 344
(2020/01/11)
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- Enantioselective Synthesis of Multisubstituted Allenes by Cooperative Cu/Pd-Catalyzed 1,4-Arylboration of 1,3-Enynes
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A cooperative Cu/Pd-catalyzed enantioselective synthesis of multisubstituted allenes is established. By employing chiral sulfoxide phosphine (SOP)/Cu and PdCl2(dppf) complexes as catalysts, the 1,4-arylboration of 1,3-enynes provides an efficient approach to trisubstituted chiral allenes with up to 92 % yield and 97:3 er. Furthermore, by using 2-substituted 1,3-enynes as substrates, the tetrasubstituted chiral allenes were successfully generated using this strategy. Finally, theoretical calculations indicate that the transmetallation of the allenylcopper species is the rate-limiting step of this transformation.
- Liao, Yang,Yin, Xuemei,Wang, Xihong,Yu, Wangzhi,Fang, Dongmei,Hu, Lianrui,Wang, Min,Liao, Jian
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supporting information
p. 1176 - 1180
(2019/12/11)
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- Triple-Bond Insertion Triggers Highly Regioselective 1,4-Aminomethylamination of 1,3-Enynes with Aminals Enabled by Pd-Catalyzed C-N Bond Activation
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A highly chemo- and regioselective 1,4-aminomethylamination of simple enynes with aminals to allenic 1,5-diamines by taking advantage of C-N bond activation has been reported. The reaction proceeds under mild reaction conditions and can be performed under
- Zhang, Yanchen,Yu, Bangkui,Gao, Binjian,Zhang, Tianze,Huang, Hanmin
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supporting information
(2019/01/21)
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- Triple-Bond Insertion Triggers Highly Regioselective 1,4-Aminomethylamination of 1,3-Enynes with Aminals Enabled by Pd-Catalyzed C-N Bond Activation
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A highly chemo- and regioselective 1,4-aminomethylamination of simple enynes with aminals to allenic 1,5-diamines by taking advantage of C-N bond activation has been reported. The reaction proceeds under mild reaction conditions and can be performed under
- Zhang, Yanchen,Yu, Bangkui,Gao, Binjian,Zhang, Tianze,Huang, Hanmin
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supporting information
p. 535 - 539
(2019/01/24)
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- Divergent Synthesis of CF3-Substituted Allenyl Nitriles by Ligand-Controlled Radical 1,2- and 1,4-Addition to 1,3-Enynes
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A ligand-controlled system that enables regioselective trifluoromethylcyanation of 1,3-enynes has been identified, which provides access to a variety of CF3-containing tri- and tetrasubstituted allenyl nitriles. We disclose that the involved propargylic radicals can be selectively trapped by (Box)CuII cyanide, while the tautomerized allenyl radicals are trapped by (phen)CuII cyanide (Box= bisoxazoline, phen=phenanthroline). In addition, the reaction features broad substrate scope and excellent functional group compatibility. Moreover, this protocol represents a novel regioselectivity-tunable functionalization of 1,3-enynes via radicals, which we believe will have great implications for the development of catalytic systems for selectivity control in radical and organometallic chemistry.
- Wang, Fei,Wang, Dinghai,Zhou, Yu,Liang, Ling,Lu, Ronghua,Chen, Pinhong,Lin, Zhenyang,Liu, Guosheng
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supporting information
p. 7140 - 7145
(2018/05/29)
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- Copper-catalyzed silylation reactions of propargyl epoxides: Easy access to 2,3-allenols and stereodefined alkenes
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Efficient silylation reactions of propargyl epoxides catalyzed by copper catalysts have been developed. Under mild reaction conditions, tri- and tetra-substituted functionalized allenols and alkenes could be selectively obtained in moderate to high yields
- Chang, Xi-Hao,Liu, Zheng-Li,Luo, Yun-Cheng,Yang, Chao,Liu, Xiao-Wei,Da, Bing-Chao,Li, Jie-Jun,Ahmad, Tanveer,Loh, Teck-Peng,Xu, Yun-He
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supporting information
p. 9344 - 9347
(2017/08/23)
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- Synthesis of cyclobutenes and allenes by cobalt-catalyzed cross-dimerization of simple alkenes with 1,3-enynes
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Cobalt-catalyzed cross-dimerization of simple alkenes with 1,3-enynes is reported. A [2+2] cycloaddition reaction occurred, with alkenes bearing no allylic hydrogen, by reductive elimination of a η3-butadienyl cobaltacycle. On the other hand, a
- Nishimura, Akira,Tamai, Eri,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 6613 - 6617
(2014/06/09)
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- Regioselective solvent-dependent benzannulation of conjugated enynes
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The transformation of enynes under cobalt-catalysis leads to symmetrical benzannulation products in dichloromethane. In tetrahydrofuran the cobalt-catalysed reactions afforded the unprecedented unsymmetrical benzannulation products in moderate to good yields and good regioselectivities. In addition, cyclotrimerisation of the alkyne subunit can be realised when electron-deficient enynes are applied in the cobalt-catalysed transformations to generate 1,2,4-trivinylbenzene derivatives using tetrahydrofuran as solvent.
- Puenner, Florian,Hilt, Gerhard
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supporting information; experimental part
p. 3617 - 3619
(2012/05/20)
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- Silver-catalyzed carbomagnesiation of terminal aryl and silyl alkynes and enynes in the presence of 1,2-dibromoethane
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Regioselective carbomagnesiation of terminal alkynes and enynes with alkyl Grignard reagents has been achieved by the combined use of a silver catalyst and 1,2-dibromoethane. The Royal Society of Chemistry 2009.
- Fujii, Yuuki,Terao, Jun,Kambe, Nobuaki
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supporting information; experimental part
p. 1115 - 1117
(2009/07/10)
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- First total synthesis of the potent anticancer natural product dideoxypetrosynol A: Preparation of the skipped (Z)-enediyne moiety by oxidative coupling of homopropargylphosphonium ylide
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Dideoxypetrosynol A is a C30 polyacetylenic alcohol with C2 symmetry. The first total synthesis of both enantiomers of the potent anti-cancer natural product (+)- and (-)-dideoxypetrosynol A is reported. The key step is an oxidative coupling of a homopropargylphosphonium ylide to prepare the skipped (Z)-enediyne moiety. The natural dideoxypetrosynol A was isolated as a racemic mixture as shown in structure 1. The absolute configurations of the chiral centers are established for the (+)- and (-)-enantiomers using Burgess' enzymatic resolution procedure with Pseudomonas AK lipase. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Gung, Benjamin W.,Omollo, Ann O.
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body text
p. 4790 - 4795
(2009/05/07)
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- Cu-catalyzed regioselective carbomagnesiation of dienes and enynes with sec- and tert-alkyl Grignard reagents
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The carbomagnesiation of dienes and enynes with sec- and tert-alkyl Grignard reagents has been achieved by using copper salts as catalysts. The Royal Society of Chemistry.
- Todo, Hirohisa,Terao, Jun,Watanabe, Hideyuki,Kuniyasu, Hitoshi,Kambe, Nobuaki
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p. 1332 - 1334
(2008/12/21)
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- Convenient access to functionalized vinylcyclopentenols from alkynyloxiranes
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β,γ-Alkynyl aldehydes, generated in situ by treatment of alkynyloxiranes with a catalytic amount of Sc(OTf)3 or BF 3· OEt2, are effectively trapped by a variety of allyl nucleophiles to afford homopropargylic homoallylic a
- Wang, Letian,Maddess, Matthew L.,Lautens, Mark
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p. 1822 - 1825
(2007/10/03)
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- Directing effects of tethered alkenes in nickel-catalyzed coupling reactions of 1,6-enynes and aldehydes
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Nickel-catalyzed reductive coupling reactions of aldehydes and 1,6-enynes proceed in excellent regioselectivity in the absence of a phosphine, and the use of a monodentate phosphine additive leads to the formation of the opposite regioisomer with equally high selectivity. Both products are the result of the same fundamental mechanism, with the inversion of regioselectivity being the result of stereospecific ligand substitution at the metal center.
- Moslin, Ryan M.,Miller, Karen M.,Jamison, Timothy F.
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p. 7598 - 7610
(2007/10/03)
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- Alkene-Directed, Nickel-Catalyzed Alkyne Coupling Reactions
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In alkene-directed, nickel-catalyzed coupling reactions of 1,3-enynes with aldehydes and epoxides, the conjugated alkene dramatically enhances reactivity and uniformly directs regioselectivity, independent of the nature of the other alkyne substituent (ar
- Miller, Karen M.,Luanphaisarnnont, Torsak,Molinaro, Carmela,Jamison, Timothy F.
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p. 4130 - 4131
(2007/10/03)
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- Olefination of activated halides and mesylates using arsonium ylides
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Alkyltriphenylarsonium ylides react with activated primary halides and mesylates to afford olefins in good yields and with high E-selectivity.
- Seyer, Andre,Alcaraz, Lilian,Mioskowski
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p. 7871 - 7874
(2007/10/03)
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- Regio- and Stereo-specific Reduction of Conjugated and Non-conjugated Triple Bonds by Activated Zinc Powder
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Regio- as well as stereo-specific reductions of a wide variety of acetylenic derivatives have been carried out in absolute ethanol with zinc powder activated with 1,2-dibromoethane, and with zinc powder activated successively with dibromoethane and copper(I) bromide, the first reagent being less powerful and more selective than the second one.
- Aerssens, Marc H. P. J.,Brandsma, Lambert
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p. 735 - 736
(2007/10/02)
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