- Rhodium-Catalyzed C?H Activation/Annulation Cascade of Aryl Oximes and Propargyl Alcohols to Isoquinoline N-Oxides
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A β-hydroxy elimination instead of common oxidization to carbonyl group in secondary propargyl alcohols was successfully developed to form 2-benzyl substituted isoquinoline N-oxides by a Rhodium-catalyzed C?H activation and annulation cascade, in which moderate to excellent yields (up to 92%) could be obtained under mild reaction conditions, along with good regioselectivity, broad generality and applicability. (Figure presented.).
- Li, Yuan,Fang, Feifei,Zhou, Jianhui,Li, Jiyuan,Wang, Run,Liu, Hong,Zhou, Yu
-
supporting information
p. 3305 - 3310
(2021/05/17)
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- Straightforward Stereoselective Synthesis of Seven-Membered Oxa-Bridged Rings through in Situ Generated Cycloheptenol Derivatives
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An iodine-mediated stereoselective synthesis of seven-membered oxa-bridged rings via in situ generated cycloheptenols was reported. This process was realized through the combination of C-C σ-bond cleavage and C-O bond-forming reactions in a one-pot fashion from simple and easily accessible raw materials. The formation of carbon radicals initiated by I2 was the key to the reaction.
- Wang, Mengdan,Yin, Liqiang,Cheng, Lu,Yang, Yajie,Li, Yanzhong
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p. 12956 - 12963
(2021/09/13)
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- Au(I)-catalyzed cycloaddition pathways of non-terminal propargyl substrates
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Novel chiral menthol-based pyridyl nitrone ligands were synthesized and Au(I) coordination of the ligands gave chiral Au(I)–nitrone complexes. 1H NMR studies of the gold(I) coordination experiments with nitrone ligands afforded a convenient method for monitoring complex formation. The catalytic effect of Au(I)–nitrone complexes, shown to tune catalytic systems to produce uncommon products, was evaluated in [2 + 2 + 2] cyclotrimerization and [2 + 4] cyclodimerization reactions of non-terminal propargyl acetals. Alternative gold(I)-catalyzed [2 + 2], [2 + 4] and [3 + 4] cycloaddition reaction pathways of non-terminal propargyl acetals with imine substrates gave a diverse range of N-heterocyclic products. The present screening study demonstrates the potential and the versatility of non-terminal propargyl acetals in gold(I)-catalyzed cycloaddition reactions.
- Siah, Huey-San Melanie,Jónsson, Helgi Freyr,Fiksdahl, Anne
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supporting information
p. 1758 - 1773
(2020/05/25)
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- Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways to Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
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A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. First, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxyimines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-amino alcohols with high syn selectivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines. A mechanism for the hydroamination has been proposed on the basis of experimental studies and density functional theory calculations.
- Laserna, Victor,Porter, Michael J.,Sheppard, Tom D.
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p. 11391 - 11406
(2019/09/30)
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- Cascade Reaction of Propargyl Amines with AgSCF3, as Well as One-Pot Reaction of Propargyl Amines, AgSCF3, and Di- tert-butyl Peroxide: Access to Allenyl Thiocyanates and Allenyl Trifluoromethylthioethers
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An efficient cascade reaction of propargyl amines with AgSCF3 and KBr is developed, affording allenyl thiocyanates at room temperature in high yields. This transformation proceeds via the in situ formation of isothiocyanate intermediates, followed by a [3,3]-sigmatropic rearrangement. The resulting allenyl thiocyanates bearing 3-(electro-donating phenyl) substitutions without isolation can then be reacted with di-tert-butyl peroxide and AgSCF3 under reflux to generate novel allenyl trifluoromethylthioether compounds in moderate to good yields via a "one-pot" three-step process.
- Zhen, Long,Yuan, Kun,Li, Xiu-Yan,Zhang, Chenyun,Yang, Jun,Fan, Hui,Jiang, Liqin
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supporting information
p. 3109 - 3113
(2018/05/28)
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- Efficient Synthesis of Polysubstituted Pyrroles Based on [3+2] Cycloaddition Strategy Utilizing [1,2]-Phospha-Brook Rearrangement under Br?nsted Base Catalysis
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An efficient method for the synthesis of polysubstituted pyrroles was established based on the [3+2] cycloaddition strategy utilizing the [1,2]-phospha-Brook rearrangement under Br?nsted base catalysis. The less-explored approach of the [3+2] cycloaddition, that is, the reaction of a C3 subunit with imines, was successfully achieved by making use of newly designed C3 subunits containing the requisite umpolung. The two-step formal [3+2] cycloaddition involves the catalytic generation of an α-oxygenated propargyl anion through the [1,2]-phospha-Brook rearrangement followed by γ-addition to the imine under Br?nsted base catalysis and the subsequent intramolecular cyclization mediated by Au catalyst or a halogenation reagent to afford polysubstituted pyrroles having a variety of substituents in a positional selective manner. The pyrroles thus synthesized were amenable to further transformations, such as palladium-catalyzed cross-coupling reactions. The operationally very simple method with readily available substrates provides new access to a diverse array of well-organized polysubstituted pyrroles.
- Kondoh, Azusa,Iino, Akio,Ishikawa, Sho,Aoki, Takuma,Terada, Masahiro
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supporting information
p. 15246 - 15253
(2018/10/15)
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- Vanadium(V)-mediated rearrangement/halogenation cascade: Synthesis of α-haloenones from propargyl alcohols
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A method is described for the oxidative Meyer–Schuster-type rearrangement of propargylic alcohols to (Z)-α-chloro- and α-iodoenones using VOCl3 as a multifunctional reagent. The vanadium reagent is found to serve as rearrangement promoter as well as an active chlorenium ion donor. Yields are improved when VOCl3 is employed in conjunction with N-halosuccinimide reagents, giving some insights into the complex mechanism.
- Zhao, Meng,Mohr, Justin T.
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p. 4115 - 4124
(2017/06/29)
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- Metal- and Acid-Free Methyl Triflate Catalyzed Meyer-Schuster Rearrangement
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A novel metal- and acid-free preparation of synthetically useful α,β-unsaturated carbonyl compounds from propargyl alcohols has been realized. This Meyer-Schuster rearrangement process is effectively catalyzed by methyl triflate (20 mol%) to prepare a broad scope of conjugated E -enals and E -enones generally in good to excellent yields (up to 90%). This reaction procedure operates under mild conditions (70 °C), in air, with short reaction times (1 h). Moreover, a carbocation intermediate trapped by the solvent 2,2,2-trifluoroethanol was isolated during this transformation.
- Yang, Lu,Zeng, Qingle
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p. 3149 - 3156
(2017/07/12)
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- Alkynylation of aldehydes mediated by zinc and allyl bromide: a practical synthesis of propargylic alcohols
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Abstract: A practical synthesis of propargylic alcohols was developed by alkynylation of aldehydes mediated by zinc and allyl bromide. Aromatic, aliphatic and vinyl aldehydes react with phenylacetylene or 1-hexyne to obtain various propargylic alcohols at room temperature in up to 98% yield. This method is characterized with inexpensive materials, wide substrate scope, and mild reaction conditions, and is also easy to scale up. In addition, this protocol is applicable to the alkynylation of α-ketone esters and epoxides to generate α-tertiary-hydroxy esters and α-alkynyl alcohols, respectively. Graphical Abstract: [Figure not available: see fulltext.].
- Zhou, Ji-Cai,Zhao, Lei,Li, Yuan,Fu, Ding-Qiang,Li, Zi-Cheng,Huang, Wen-Cai
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p. 4283 - 4294
(2017/06/20)
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- Cadmium(II) Chloride-Catalyzed Dehydrative C?P Coupling of Propargyl Alcohols with Diarylphosphine Oxides to Afford Allenylphosphine Oxides
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The cadmium(II) chloride-catalyzed dehydrative C?P cross-coupling reaction of propargyl alcohols with diarylphosphine oxides is reported. Several propargyl alcohols including those bearing the sterically demanding tert-butyl group at the triple bond terminus can be used as good substrates in the reaction to produce the corresponding allenylphosphine oxides in good to high yields in acetonitrile at 100 °C. The reaction can also be easily scaled up to a gram-scale synthesis. A mechanism study indicates that the reaction may proceed through a process of propargylic substitution to generate phosphonite intermediates followed by [2,3] sigmatropic rearrangement to produce the allenyl products, rather than through a common allenylative substitution resulting from P-nucleophilicity. (Figure presented.).
- Yang, Jianlin,Zhang, Ming,Qiu, Kang,Wang, Lize,Yu, Jingjing,Xia, Zefeng,Shen, Ruwei,Han, Li-Biao
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supporting information
p. 4417 - 4426
(2017/12/26)
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- Synthesis of Vinyl-, Allyl-, and 2-Boryl Allylboronates via a Highly Selective Copper-Catalyzed Borylation of Propargylic Alcohols
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An efficient methodology for the synthesis of vinyl-, allyl-, and (E)-2-boryl allylboronates from propargylic alcohols via Cu-catalyzed borylation under mild conditions is reported. In the presence of commercially available Cu(OAc)2 or Cu(acac)2 and Xantphos, the reaction affords the desired products in up to 92% yield with a broad substrate scope (43 examples). Isolation of an allenyl boronate as the reaction intermediate suggests that an insertion-elimination-type reaction, followed by borylcupration, is involved in the borylation of propargylic alcohols.
- Mao, Lujia,Bertermann, Rüdiger,Emmert, Katharina,Szabó, Kálmán J.,Marder, Todd B.
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supporting information
p. 6586 - 6589
(2017/12/26)
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- Rhodium-Catalyzed/Copper-Mediated Tandem C(sp2)-H Alkynylation and Annulation: Synthesis of 11-Acylated Imidazo[1,2-a:3,4-a′]dipyridin-5-ium-4-olates from 2H-[1,2′-Bipyridin]-2-ones and Propargyl Alcohols
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A rhodium-catalyzed/copper-mediated tandem C(sp2)-H alkynylation and intramolecular annulation of 2H-[1,2′-bipyridin]-2-ones with propargyl alcohols for the synthesis of 11-acylated imidazo[1,2-a:3,4-a′]dipyridin-5-ium-4-olates is described.
- Li, Ting,Wang, Zhiqiang,Xu, Kun,Liu, Wenmin,Zhang, Xu,Mao, Wutao,Guo, Yongming,Ge, Xiaolin,Pan, Fei
-
supporting information
p. 1064 - 1067
(2016/03/15)
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- Catalytic α-Allylation of Enones with Alcohols via [Gold(I)]-Mediated [3,3]-Sigmatropic Rearrangement of Propargylic Carboxylates
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The site-selective α-allylic alkylation of enones with alcohols via gold-triggered formation of nucleophilic allenoates by means of [3,3]-sigmatropic rearrangements of propargylic carboxylates is reported. A range of α-alkylated enones is obtained in high yields in the presence of the gold complex [JohnPhosAu(ACN)]SbF6 (2 mol%) as the promoting agent. Examples of allylation/Friedel-Crafts alkylation sequences are also provided, delivering densely functionalized dihydroindenes and dihydrobenzo[7]annulenes in a one-pot procedure in moderate yields. The role of the Br?nsted acidity (i.e., pivalic acid) delivered during the reaction course in assisting the formation of carbocationic intermediates is documented.
- Manoni, Elisabetta,Daka, Mario,Mastandrea, Marco M.,Nisi, Assunta De,Monari, Magda,Bandini, Marco
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supporting information
p. 1404 - 1409
(2016/05/19)
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- Regio- and stereo-selective intermolecular [2+2] cycloaddition of allenol esters with C60 leading to alkylidenecyclobutane-annulated fullerenes
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The intermolecular [2+2] cycloaddition of allenol esters, which were in situ generated by Pt-catalyzed 1,3-acyloxy migration of propargylic esters, with C60 proceeded regio- and stereo-selectively to give a novel class of alkylidenecyclobutane-annulated fullerenes. The cyclobutane-annulated fullerene derivatives have high-lying LUMO levels, which gave a high open-circuit voltage in organic solar cell applications. The observed high electron mobility provided a good fill factor compared with the PCBM-based devices.
- Ueda, Mitsuhiro,Sakaguchi, Tsukasa,Hayama, Miho,Nakagawa, Takafumi,Matsuo, Yutaka,Munechika, Aiko,Yoshida, Shunsuke,Yasuda, Hiroshi,Ryu, Ilhyong
-
supporting information
p. 13175 - 13178
(2016/11/09)
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- Gold(I)-catalyzed decarboxylation of propargyl carbonates: Reactivity reversal of the gold catalyst from π-Lewis acidity to σ-Lewis acidity
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A cationic gold(I)-catalyzed decarboxylative etherification of propargyl carbonates to selectively produce propargyl ethers is reported. In the reaction the gold(I) catalyst shows a distinct σ-Lewis acidity rather than the commonly observed π-Lewis acidity, and thus catalyzes the decarboxylation of a variety of propargyl carbonates to give the corresponding propargyl ethers with high selectivity. This reaction represents a rare example of the tunable reactivity of cationic gold(I) complexes between σ-Lewis acidity and π-Lewis acidity.
- Shen, Ruwei,Yang, Jianjun,Zhu, Shugao,Chen, Chao,Wu, Luling
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p. 1259 - 1269
(2015/04/22)
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- Dehydrogenative Meyer-Schuster-like rearrangement: A gold-catalyzed reaction generating an alkyne
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Easily accessible propargylic esters are converted to the inverted alkynyl ketones in an oxidative gold-catalyzed reaction. Gagosz's catalyst in combination with PhI(OAc)2 is the best system for this conversion and 18 examples with yields up to 80 % are reported. The results indicate that the triple bond in the product is formed by elimination from a vinylgold intermediate. In a formal sense the new conversion overall is a dehydrogenative Meyer-Schuster rearrangement. It takes alkynes: Propargyl esters can be converted into alkynyl ketones by a new oxidative gold-catalyzed reaction. The best catalyst system is Ph3PAuCl/AgNTf2 in combination with the oxidant PhI(OAc)2. The yields are as high as 80 % and the reaction can be conducted in the presence of air. Copyright
- Yu, Yang,Yang, Weibo,Pflaesterer, Daniel,Hashmi, A. Stephen K.
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supporting information
p. 1144 - 1147
(2014/03/21)
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- Silver-catalyzed efficient synthesis of vinylene carbonate derivatives from carbon dioxide
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It was found that the silver salt and base was an efficient catalytic system for the reaction of the secondary propargylic alcohol with carbon dioxide to afford various corresponding vinylene carbonate derivatives in good to high yields under mild conditions. Georg Thieme Verlag Stuttgart New York.
- Ugajin, Rie,Kikuchi, Satoshi,Yamada, Tohru
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supporting information
p. 1178 - 1180
(2014/05/20)
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- Highly diastereoselective synthesis of cyclopentenones via a one-pot gold catalysis, Nazarov cyclization and alkylation cascade
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Starting from readily available propargylic carboxylates, three sequential transformations [gold-catalyzed tandem reaction, scandium(III) trifluoromethanesulfonate catalyzed Nazarov cyclization, alkylation reaction] in a one-pot process led to the formation of cyclopentenone derivatives in excellent diastereoselectivities and moderate to good overall yields. Georg Thieme Verlag Stuttgart. New York.
- Liu, Meng-Qi,Zhou, Ai-Hua,Jiang, Shuang,Wang, Jia-Qi,Ye, Long-Wu
-
supporting information
p. 2161 - 2167
(2014/08/18)
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- Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with alkynyl ketones and alkynyl esters
-
We found that the combination of [Ir(cod)Cl]2 and rac-BINAP served as an efficient catalyst for the [2+2+2] cycloaddition of 2,7-nonadiyne derivatives and related compounds with alkynyl ketones and alkynyl esters. The corresponding products wer
- Hashimoto, Toru,Okabe, Arisa,Mizuno, Takeshi,Izawa, Mao,Takeuchi, Ryo
-
supporting information
p. 8681 - 8689
(2015/01/09)
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- A mild and efficient AgSbF6-catalyzed synthesis of fully substituted pyrroles through a sequential propargylation/amination/ cycloisomerization reaction
-
Development of an efficient synthesis of fully substituted pyrroles via a sequential propargylation/amination/cycloisomerization was accomplished using AgSbF6 as a catalyst. The one-pot three-component reaction of propargylic alcohols, 1,3-dica
- Gujarathi, Satheesh,Liu, Xingui,Song, Lin,Hendrickson, Howard,Zheng, Guangrong
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p. 5267 - 5273
(2014/07/08)
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- Regioselective rapid synthesis of fully substituted 1,2,3-triazoles mediated by propargyl cations
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Regioselective rapid triazole syntheses at low temperature are described. Organic azides and propargyl cations generated by acids gave fully substituted 1H-1,2,3-triazoles. Most reactions could be performed in 5 min at not only rt but also -90 C. Both terminal and internal alkynes were acceptable, and the sterically bulky substituents could afford the products smoothly. Various types of three-component coupling reactions were demonstrated, and the presence of allenylaminodiazonium intermediates was indicated.
- Zhang, Huan,Tanimoto, Hiroki,Morimoto, Tsumoru,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi
-
supporting information
p. 5222 - 5225
(2013/11/06)
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- Catalytic asymmetric enyne addition to aldehdyes and Rh(I)-catalyzed stereoselective domino Pauson-Khand/[4 + 2] cycloaddition
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The 1,1′-bi-2-naphthol-ZnEt2-Ti(OiPr) 4-Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75-96% yield and 82-97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson-Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaternary chiral carbon center.
- Chen, Wei,Tay, Jia-Hui,Ying, Jun,Yu, Xiao-Qi,Pu, Lin
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p. 2256 - 2265
(2013/04/24)
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- Condensation of propargylic alcohols with N-methylcarbazole and carbazole in [bmim]PF6 ionic liquid; Synthesis of novel dipropargylic carbazoles using TfOH or Bi(NO3)3·5H2O as catalyst
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A series of doubly-propargylated N-methylcarbazole and carbazole derivatives were synthesized in good to excellent isolated yields in (bmim)PF6 using triflic acid (10 mol %). The use of bismuth nitrate (20 mol %) instead of triflic acid allowed stepwise propargylation employing two different propargylic alcohols, to prepare mixed bis-propargylated carbazoles. Simple product isolation, mild reaction conditions, and repeated recycling and reuse of (bmim)PF6 are added advantages of this IL-mediated synthetic method.
- Kumar, G.G.K.S. Narayana,Laali, Kenneth K.
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p. 965 - 969
(2013/03/13)
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- Gold meets rhodium: Tandem one-pot synthesis of β-disubstituted ketones via meyer-schuster rearrangement and asymmetric 1,4-addition
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An asymmetric one-pot tandem Au/Rh-catalyzed synthesis of highly enantioenriched β-disubstituted ketones starting from racemic propargyl alcohols is disclosed. The compatibility of the two metal complexes (Au/Rh) and their orthogonal ligand systems (NHC/d
- Hansmann, Max M.,Hashmi, A. Stephen K.,Lautens, Mark
-
supporting information
p. 3226 - 3229
(2013/07/26)
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- Regioselective catalytic hydroboration of propargylic species using Cu(I)-NHC complexes
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The catalytic regioselective hydroboration of propargylic alcohols and ethers was investigated using NHC-CuCl. We observe that different NHCCuCl complexes catalyze hydroborations of propargylic substrates with opposite regioselectivity. A 6-NHC-CuCl complex provides R-selectivity whereas β-selectivity is achieved using a 5-NHC-CuCl complex. The reaction tolerates a wide range of functional groups.
- Park, Jin Kyoon,Ondrusek, Brian A.,McQuade, D. Tyler
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supporting information
p. 4790 - 4793
(2013/01/15)
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- A concise access to (polyfluoroaryl)allenes by Cu-catalyzed direct coupling with propargyl phosphates
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A copper-based catalyst system for the direct coupling of polyfluoroarenes with propargyl phosphates has been developed. The catalysis can provide a rapid and concise access to (polyfluoroaryl)allenes, which can be important building blocks for the synthesis of fluorinated functional materials.
- Nakatani, Akihiro,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 2586 - 2589
(2012/07/30)
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- Gold- and silver-catalyzed reactions of propargylic alcohols in the presence of protic additives
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A wide range of primary, secondary and tertiary propargylic alcohols undergo a Meyer-Schuster rearrangement to give enones at room temperature in the presence of a gold(I) catalyst and small quantities of MeOH or 4-methoxyphenylboronic acid. The syntheses of the enone natural products isoegomaketone and daphenone were achieved using this reaction as the key step. The rearrangement of primary propargylic alcohols can readily be combined in a one-pot procedure with the addition of a nucleophile to the resulting terminal enone, to give β-aryl, β-alkoxy, β-amino or β-sulfido ketones. Propargylic alcohols bearing an adjacent electron-rich aryl group can also undergo silver-catalyzed substitution of the alcohol with oxygen, nitrogen and carbon nucleophiles. This latter reaction was initially observed with a batch of gold catalyst that was probably contaminated with small quantities of silver salt.
- Pennell, Matthew N.,Turner, Peter G.,Sheppard, Tom D.
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supporting information; experimental part
p. 4748 - 4758
(2012/05/04)
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- A convenient approach to β-heteroarylated (C-N bond) ketones from Cs2CO3 promoted reaction between propargyl alcohols and nitrogen-heterocycles
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An efficient and direct approach to β-heteroarylated (C-N bond) ketones is demonstrated. Base promoted redox isomerization of propargyl alcohol to α,β-unsaturated ketone followed by conjugate addition to NH-heteroarenes affords a wide range of β-heteroarylated ketones in good to excellent yields. Aryl, heteroaryl, alkyl C(sp), and terminal alkynes containing unactivated propargyl alcohols effectively undergo redox-isomerization conjugate addition (RICA) with NH-heteroarenes. Reaction of 3-substituted pyrazoles or indazole with propargyl alcohols enables highly regioselective products. A diverse range of NH-bearing nucleophiles such as: pyrazoles, imidazole, triazoles, pyrrole, indoles and aniline participate in this reaction and deliver the corresponding β-heteroarylated ketones.
- Bhanuchandra,Kuram, Malleswara Rao,Sahoo, Akhila K.
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experimental part
p. 3538 - 3555
(2012/05/20)
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- Gold-catalyzed isomerization of unactivated allenes into 1,3-dienes under ambient conditions
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We have developed a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.
- Ting, Chun-Ming,Hsu, Yi-Ling,Liu, Rai-Shung
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supporting information; experimental part
p. 6577 - 6579
(2012/07/31)
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- One-pot consecutive reactions based on the synthesis of conjugated enones by the re-catalysed meyer-schuster rearrangement
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Re catalysis in one-pot reactions: An atom-economical, one-pot strategy that involves alkyne deprotonation and a subsequent rhenium(V)-catalysed Meyer-Schuster rearrangement of the alkynol to provide α,β- unsaturated enones in high yield has been developed (see scheme). Subsequent in situ hydride reduction or Diels-Alder reaction of the enones provided products in good-to-high overall yields. Copyright
- Mattia, Elio,Porta, Alessio,Merlini, Valentina,Zanoni, Giuseppe,Vidari, Giovanni
-
supporting information
p. 11894 - 11898
(2012/10/29)
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- Spirodiepoxide-based cascades: Direct access to diverse motifs
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Allene epoxide formation/opening reaction sequences enabled direct access to diverse products. Described here are a single flask procedure for allene preparation and allene oxidation/derivatization reactions that give, among others, diendiol, diyndiol, α′-hydroxy-γ-enone, dihydrofuranone, butenolide, and δ-lactone products.
- Sharma, Rojita,Manpadi, Madhuri,Zhang, Yue,Kim, Hiyun,Ahkmedov, Novruz G.,Williams, Lawrence J.
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supporting information; experimental part
p. 3352 - 3355
(2011/08/22)
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- Highly enantioselective addition of linear alkyl alkynes to aromatic aldehydes
-
An asymmetric linear alkyl alkyne addition to aromatic aldehydes catalyzed by the Ti-(R)-BINOL system is reported with high enantioselectivity and yield. Our study expands upon the synthetic scope of propargylic alcohols, which could serve as potentially useful intermediates for the synthesis of various natural products.
- Du, Xi,Wang, Qin,He, Xiao,Peng, Rui-Guang,Zhang, Xiao,Yu, Xiao-Qi
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experimental part
p. 1142 - 1146
(2011/10/08)
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- A new and general one-pot synthesis of propargyl alcohols from esters
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Intermediates easily prepared by partial reduction of various esters with LDBBA as a reducing agent smoothly react with lithium acetylides to give propargyl alcohols, without isolation of partial reduction intermediates, in good yields (73-83%).
- Chae, Min Jung,Jeon, Ah Ram,Livinghouse, Tom,An, Duk Keun
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experimental part
p. 3281 - 3283
(2011/05/05)
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- Tetrabutylammonium fluoride (TBAF)-catalyzed addition of substituted trialkylsilylalkynes to aldehydes, ketones, and trifluoromethyl ketones
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Herein we report that tetrabutylammonium fluoride (TBAF) is a very efficient catalyst for the addition of trialkylsilylalkynes to aldehydes, ketones, and trifluoromethyl ketones in THF solvent at room temperature. The reaction conditions are mild and oper
- Chintareddy, Venkat Reddy,Wadhwa, Kuldeep,Verkade, John G.
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supporting information; experimental part
p. 4482 - 4488
(2011/07/30)
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- Synthesis of phosphine-ligated zinc acetylide dimers: Enhanced reactivity in carbonyl additions
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Phosphine-ligated dinuclear zinc acetylides effectively promote the alkynylation of carbonyl derivatives. Good to excellent yields (46-91%) of the corresponding propargylic alcohols were obtained from a wide range of substrates. Crystallographic evidence
- Wilson, Erin E.,Oliver, Allen G.,Hughes, Russell P.,Ashfeld, Brandon L.
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experimental part
p. 5214 - 5221
(2011/11/13)
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- Enantioselective alkynylation of aldehydes with 1-haloalkynes catalyzed by tethered bis(8-quinolinato) chromium complex
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The first example of Cr-catalyzed asymmetric alkynylation of aldehydes with 1-iodo- and 1-bromoalkynes was developed. The use of tethered bis(8-quinolinato) chromium catalyst (3 mol %) allowed preparation of enantioenriched propargyl alcohols with good yields and enantioselectivities up to 92% ee. 1-Bromoalkynes can be activated by the introduction of a cobalt porphine cocatalyst, which enables shorter reaction times without any loss of enantiocontrol.
- Usanov, Dmitry L.,Yamamoto, Hisashi
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supporting information; experimental part
p. 1286 - 1289
(2011/04/16)
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- Iron-catalyzed C-O bond activation for the synthesis of propargyl-1,2,3-triazoles and 1,1-bis-triazoles
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(Equation Presented). The FeCl3-catalyzed triazole propargylation was developed. This transformation was suitable for a large scope of substituted propargyl alcohols, giving the corresponding propargyl triazoles in excellent yields (up to 96%). Further derivatization produced the 1,1-bis-triazoles in excellent yields and regioselectivity, which could be applied as potential transition metal ligands or new reagents.
- Yan, Wuming,Wang, Qiaoyi,Chen, Yunfeng,Petersen, Jeffrey L.,Shi, Xiaodong
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supporting information; experimental part
p. 3308 - 3311
(2010/10/19)
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- Selective synthesis of allenes and alkynes through ligand-controlled, palladium-catalyzed decarboxylative hydrogenolysis of propargylic formates
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Ligand-controlled regioselective palladium-catalyzed decarboxylative hydrogenolysis of propargylic formates is described. A wide range of allenes and alkynes were obtained by using either 1,2-diphenylphosphinoethane (DPPE) or 1,6-bisdiphenylphosphinohexane (DPPH) as a catalyst ligand.
- Ohmiya, Hirohisa,Yang, Mingyu,Yamauchi, Yoshihiro,Ohtsuka, Yuhki,Sawamura, Masaya
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supporting information; experimental part
p. 1796 - 1799
(2010/09/07)
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- Mild and expedient asymmetric reductions of α,β-unsaturated alkenyl and alkynyl ketones by TarB-NO2 and mechanistic investigations of ketone reduction
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A facile and mild reduction procedure is reported for the preparation of chiral allylic and propargyl alcohols in high enantiomeric purity. Under optimized conditions, alkynyl and alkenyl ketones were reduced by TarB-NO 2 and NaBH4 at 25 °C in 1 h to produce chiral propargyl and allylic alcohols with enantiomeric excesses and yields up to 99%. In the case of α,β-unsaturated alkenyl ketones, α-substituted cycloalkenones were reduced with up to 99% ee, while more substituted and acyclic derivatives exhibited lower induction. For α,β-ynones, it was found that highly branched aliphatic ynones were reduced with optimal induction up to 90% ee, while reduction of aromatic and linear aliphatic derivatives resulted in more modest enantioselectivity. Using the (l)-TarB-NO2 reagent derived from (l)-tartaric acid, we routinely obtained highly enantioenriched chiral allylic and propargyl alcohols with (R) configuration. Since previous models and a reduction of a saturated analogue predicted propargyl products of (S) configuration, a series of new mechanistic studies were conducted to determine the likely orientation of aromatic, alkenyl, and alkynyl ketones in the transition state.
- Eagon, Scott,Delieto, Cassandra,McDonald, William J.,Haddenham, Dustin,Saavedra, Jaime,Kim, Jinsoo,Singaram, Bakthan
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experimental part
p. 7717 - 7725
(2011/01/05)
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- Palladium-catalyzed intramolecular carbopalladation/cyclization cascade: Access to polycyclic N-fused heterocycles
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An efficient palladium-catalyzed intramolecular carbopalladation/ cyclization cascade toward tetra- and pentacyclic N-fused heterocycles has been developed. This transformation proceeds via the palladium-catalyzed coupling of aryl halides with internal propargylic esters or ethers followed by the 5-endo-dig cyclization leading to polycyclic pyrroloheterocycles in moderate to excellent yields.
- Chernyak, Dmitri,Gevorgyan, Vladimir
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supporting information; experimental part
p. 5558 - 5560
(2011/02/25)
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- New application of n-halosuccinimide/PPh3 for the halogenation of propargyl alcohols to haloallenes
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An efficient and convenient new method has been developed for the preparation of haloallenes from propargyl alcohols by a reagent combination of N-halosuccinimide and triphenylphosphine. Chloroallenes 2 and bromoallenes 3 were obtained exclusively in mode
- Du, Xin,Dai, Yao,He, Ren,Lu, Shirong,Bao, Ming
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experimental part
p. 3940 - 3949
(2010/03/25)
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- Catalytic deprotonative functionalization of propargyl silyl ethers with imines
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A metal-free, catalytic C-H functionalization of propargyl silyl ethers with imines using the phosphazene base (t-Bu-P4 base) provides structurally defined multisubstituted pyrroles in modest to excellent yields under mild conditions. A one-pot, three-component reaction using silylated acetylenes, aldehydes, and imines is also presented.
- Naka, Hiroshi,Koseki, Daiki,Kondo, Yoshinori
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supporting information; experimental part
p. 1901 - 1906
(2009/08/07)
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- Siloxyallenes revisited. A useful functional intermediate for the synthesis of (Z)-β-branched Morita-Baylis-Hillman type adducts and (Z)-chalcones
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Siloxyallenes proved to be a useful functional intermediate in the preparation of (Z)-β-branched Morita-Baylis-Hillman type adducts by the reaction of aldehydes with silylacetylenes or siloxypropynes. Various (Z)-chalcones were stereoselectively synthesized from siloxypropynes via siloxyallenes.
- Yoshizawa, Kazuhiro,Shioiri, Takayuki
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p. 6259 - 6286
(2008/02/04)
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- [(NHC)AuI]-catalyzed formation of conjugated enones and enals: An experimental and computational study
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The [(NHC)AuI]-catalyzed (NHC = N-heterocyclic carbene) formation of α,β-unsaturated carbonyl compounds (enones and enals) from propargylic acetates is described. The reactions occur at 60°C in 8 h in the presence of an equimolar mixture of [(NHC)AuCl] and AgSbF6 and produce conjugated enones and enals in high yields. Optimization studies revealed that the reaction is sensitive to the solvent, the NHC, and, to a lesser extent, to the silver salt employed, leading to the use of [(ItBu)AuCl]/ AgSbF6 in THF as an efficient catalytic system. This transformation proved to have a broad scope, enabling the stereoselective formation of (E)-enones and -enals with great structural diversity. The effect of substitution at the propargylic and acetylenic positions has been investigated, as well as the effect of aryl substitution on the formation of cinnamyl ketones. The presence or absence of water in the reaction mixture was found to be crucial. From the same phenylpropargyl acetates, anhydrous conditions led to the formation of indene compounds via a tandem [3,3] sigmatropic rearrangement/intramolecular hydroarylation process, whereas simply adding water to the reaction mixture produced enone derivatives cleanly. Several mechanistic hypotheses, including the hydrolysis of an allenol ester intermediate and SN2′ addition of water, were examined to gain an insight into this transformation. Mechanistic investigations and computational studies support [(NHC)AuOH], produced in situ from [(NHC)AuSbF6] and H 2O, instead of cationic [(NHC)AuSbF6] as the catalytically active species. Based on DFT calculations performed at the B3LYP level of theory, a full catalytic cycle featuring an unprecedented transfer of the OH moiety bound to the gold center to the C≡C bond leading to the formation of a gold-allenolate is proposed.
- Marion, Nicolas,Carlqvist, Peter,Gealageas, Ronan,De Fremont, Pierre,Maseras, Feliu,Nolan, Steven P.
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p. 6437 - 6451
(2008/02/13)
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- Bisoxazolidine-catalyzed enantioselective alkynylation of aldehydes
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A C2-symmetric bisoxazolidine derived from aminoindanol has been successfully applied in the asymmetric alkynylation of aldehydes. The ligand is readily available, has a wide substrate scope, and catalyzes the formation of chiral propargylic alcohols with excellent yields and enantioselectivties. Copyright
- Wolf, Christian,Liu, Shuanglong
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p. 10996 - 10997
(2007/10/03)
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- Metal-free catalytic nucleophilic substitution of propargylic alcohols
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Organic acids such as PTS efficiently catalyze direct nucleophilic substitutions of the hydroxy groups of propargylic alcohols with a large variety of carbon- and heteroatom-centered nucleophiles. Reactions can be conducted under mild conditions and in air without the need for dried solvents. Reactions on multigram scales are also possible. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Sanz, Roberto,Martinez, Alberto,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 1383 - 1386
(2007/10/03)
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- Synthesis of β-branched Morita-Baylis-Hillman-type adducts from 1,3-diaryl-2-propynyl trimethylsilyl ethers and aldehydes catalyzed by potassium tert-butoxide
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1,3-Diaryl-2-propynyl trimethylsilyl ethers were easy to isomerize into the corresponding siloxyallenes using a catalytic amount of potassium tert-butoxide under very mild conditions. The siloxyallenes reacted in situ with various aldehydes to afford Z-selective β-branched Morita-Baylis-Hillman-type adducts in a one-pot reaction after acid treatment.
- Yoshizawa, Kazuhiro,Shioiri, Takayuki
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p. 757 - 761
(2007/10/03)
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- AuI-catalyzed tandem [3,3] rearrangement-intramolecular hydroarylation: Mild and efficient formation of substituted indenes
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(Chemical Equation Presented) Dignified auration: The rearrangement of phenylpropargyl acetates to substituted indenes is catalyzed by [Au 1(NHC)] complexes (see scheme, NHC = N-heterocyclic carbene) under extremely mild reaction conditions. This chemoselective transformation involves 1,3-migration of the acetate group and is proposed to proceed through an allene intermediate. TMS = trimethylsilyl, TBS = tert-butyldimethylsilyl.
- Marion, Nicolas,Diez-Gonzalez, Silvia,De Fremont, Pierre,Noble, April R.,Nolan, Steven P.
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p. 3647 - 3650
(2008/03/11)
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- Solvent-free reduction of aldehydes and ketones using solid acid-activated sodium borohydride
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A simple and convenient procedure for the reduction of aldehydes and ketones with sodium borohydride activated by solid acids such as boric acid, benzoic acid, and p-toluenesulfonic acid monohydrate under solvent-free conditions is described.
- Cho, Byung Tae,Kang, Sang Kyu,Kim, Min Sung,Ryu, Soo Ryeon,An, Duk Keun
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p. 8164 - 8168
(2007/10/03)
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