- Modular synthesis of 3-substituted isocoumarinsviasilver-catalyzed aerobic oxidation/6-endoheterocyclization ofortho-alkynylbenzaldehydes
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A method involving silver-catalyzed aerobic oxidation/6-endoheterocyclization ofortho-alkynylbenzaldehydes to yield 3-substituted isocoumarins is described. The developed protocol allows convenient access to a range of synthetically useful 3-substituted isocoumarins and related fused heterocyclolactones in good to high yields, using silver tetrafluoroborate as the catalyst, and atmospheric oxygen as the terminal oxidant and the source of endocyclic oxygen. Mechanistic studies suggest the involvement of a free-radical pathway.
- Wu, Hao,Wang, Yi-Chun,Shatskiy, Andrey,Li, Qiu-Yan,Liu, Jian-Quan,K?rk?s, Markus D.,Wang, Xiang-Shan
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p. 6657 - 6664
(2021/08/16)
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- Synthesis of substituted 1,2-dihydroisoquinolinesviaNi(ii) and Cu(i)/Ag(i) catalyzed double nucleophilic addition of arylamines toortho-alkynyl donor-acceptor cyclopropanes (o-ADACs)
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A concise approach for the synthesis of substituted 1,2-dihydroisoquinolinesviadouble nucleophilic addition of primary arylamines toortho-alkynyl donor-acceptor cyclopropanes (o-ADACs) in the presence of a catalytic Ni(ClO4)2·6H2O and CuI/AgOTf system has been developed. Further applying this protocol, some of the derived malonates were converted into the corresponding monoesters under Krapcho decarboxylation reaction conditions. Thereafter, these esters were transformed into the respective acids and alcohols. In addition, multifunctionalized 4-(2,2,2-trifluoroacetyl) 1,2-dihydroisoquinolines were also obtained with excess TFAA.
- Chahal, Kapil,Reddy, Kallu Rajender,Unnava, Ramanjaneyulu
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supporting information
p. 6025 - 6029
(2021/07/21)
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- Regio- and stereoselective intramolecular hydroalkoxylation of aromatic alkynols: an access to dihydroisobenzofurans under transition-metal-free conditions
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An efficient, transition-metal-free method to synthesize dihydroisobenzofuran derivatives via intramolecular hydroalkoxylation of aromatic alkynols with the promotion of cesium carbonate has been developed. The reaction proceeds regioselectively with exclusive formation of 5-exo-dig product, and only Z-isomer of the new generated double bond is observed. This new protocol features with milder reaction conditions, more convenient operation and satisfactory selectivities.
- Yu, Shu-Yan,Gao, Li-Hong,Wu, Jing-Xin,Lan, Hong-Bing,Ma, Yi,Yin, Zhi-Gang
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p. 3303 - 3310
(2020/04/27)
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- Selective Divergent Synthesis of Indanols, Indanones, and Indenes via Acid-Mediated Cyclization of (Z)- and (E)-(2-Stilbenyl)methanols and Its Application for the Synthesis of Paucifloral F Derivatives
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Starting from bromo/iodobenzaldehyde derivatives, the corresponding (Z)- and (E)-(2-stilbenyl)methanols could be prepared in 2-5 steps via Pd-catalyzed cross-coupling reactions (Sonogashira and Heck reactions) followed by aryllithium/aryl Grignard addition. For the (E)-stilbenes, subsequent acid-mediated cyclization using p-TsOH immobilized on silica (PTS-Si) at low temperatures furnished the 2,3-trans-1-indanols with complete stereocontrol at the C2-C3. Further oxidization of the alcohol provided the indanones, which are structurally related to the natural product paucifloral F. At higher temperatures, 1,2- and 2,3-disubstituted indenes could be selectively prepared in good to excellent yields. On the other hand, the (Z)-stilbenes, under similar conditions (PTS-Si), did not give the indanols; only the 1,2-disubstituted indenes could be obtained. To gain further insights into the stereochemistry at C2-C3 for the (Z)-stilbenes, hydride or azide was employed as a nucleophile; the corresponding indane products were obtained with the cis stereochemistry at the C2-C3. Thus, the (Z)- or (E)-olefin geometry of the substrate directed the stereoselective indanyl cyclization to furnish the cis or trans at the C2-C3 ring junction, respectively, while reaction conditions controlled the selectivity of the product types.
- Jongcharoenkamol, Jira,Chuathong, Patsapon,Amako, Yuka,Kono, Masato,Poonswat, Kasam,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 13184 - 13210
(2018/11/02)
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- Ferrocenyl bisoxazoline as an efficient non-phosphorus ligand for palladium-catalyzed copper-free Sonogashira reaction in aqueous solution
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Pd(OAc)2-catalyzed Sonogashira coupling reactions of alkynes and a variety of aryl halides with 1,3-bis(5-ferrocenylisoxazoline-3-yl)benzene as an efficient non-phosphorus ligand under copper-free conditions are presented. The main advantages over previous methodologies include low catalyst loading (0.2 mol% Pd(OAc)2 and 0.4 mol% ferrocenyl bisoxazoline ligand are sufficient for these coupling reactions), less problematic reaction medium (water–dimethylformamide) and more convenient operation (no requirement for nitrogen protection).
- Yu, Shuyan,Wu, Jingxin,He, Xinwei,Shang, Yongjia
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- Construction of Six-Membered Silacyclic Skeletons via Platinum-Catalyzed Tandem Hydrosilylation/Cyclization with Dihydrosilanes
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Catalytic silicon-carbon or silicon-heteroatom bond-forming hydrosilylation has become increasingly important in synthetic chemistry, catalysis and organosilicon chemistry. Herein we report a platinum-catalyzed one-pot and tandem hydrosilylation/cyclization of OH-containing alkynes with dihydrosilanes, allowing for facile synthesis of six-membered organosilicon compounds, including silyloxycycles and cyclic siloxanes in high yields and with good stereoselectivities. (Figure presented.).
- Long, Peng-Wei,Bai, Xing-Feng,Ye, Fei,Li, Li,Xu, Zheng,Yang, Ke-Fang,Cui, Yu-Ming,Zheng, Zhan-Jiang,Xu, Li-Wen
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supporting information
p. 2825 - 2830
(2018/08/17)
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- Cobalt-catalyzed regioselective syntheses of indeno[2,1-: C] pyridines from nitriles and diynes bearing propargyl fragments
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A highly efficient CoI2/o-phenanthroline catalyzed cycloaddition reaction of diynes bearing TBS protected propargylic alcohol fragments with nitriles has been developed. This methodology offers regioselective access, with good functional group tolerance, to various indeno[2,1-c]pyridine derivatives in moderate to excellent yields. It was found that o-phenanthroline as a bidentate nitrogen ligand showed high efficacy in this cycloaddition reaction.
- Xu, Murong,Zheng, Zhong,Wang, Mengdan,Kong, Lingkai,Ao, Yujuan,Li, Yanzhong
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supporting information
p. 8761 - 8768
(2018/11/30)
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- A gold-catalyzed cycloisomerization/aerobic oxidation cascade strategy for 2-aryl indenones from 1,5-enynes
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A unique gold(i)-catalyzed 5-endo-dig cyclization/aerobic oxidation cascade strategy from 1,5-enyne substrates with molecular oxygen as the oxidant to yield the indenone was described. The reaction mechanism was studied by heavy atom labelling and some related experiments. This method was applied to the formal total synthesis of isoprekinamycin.
- Guo, Jia,Peng, Xiaoshi,Wang, Xiaoyu,Xie, Fukai,Zhang, Xinhang,Liang, Guoduan,Sun, Zenghui,Liu, Yongxiang,Cheng, Maosheng,Liu, Yang
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supporting information
p. 9147 - 9151
(2019/01/03)
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- Visible-Light-Promoted Generation of α-Ketoradicals from Vinyl-bromides and Molecular Oxygen: Synthesis of Indenones and Dihydroindeno[1,2-c]chromenes
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Ortho-alkynylated α-bromocinnamates can be converted by a visible-light-mediated photocascade reaction with molecular oxygen into either indenones or dihydroindeno[1,2-c]chromenes. The one-step process features key photochemical steps, that is, the initial activation of vinyl bromides through energy transfer to give α-ketoradicals in a reaction with molecular oxygen, followed by α-oxidation of an arene moiety by 6-π electrocyclization, and subsequent hydroxylation by an electron-transfer process from the same photocatalyst leads to the dihydroindeno[1,2-c]chromenes.
- Pagire, Santosh K.,Kreitmeier, Peter,Reiser, Oliver
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supporting information
p. 10928 - 10932
(2017/08/30)
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- Palladium-Catalyzed Copper-Free Sonogashira Coupling of 2-Bromoarylcarbonyls: Synthesis of Isobenzofurans via One-Pot Reductive Cyclization
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Palladium-catalyzed copper-free Sonogashira coupling of 2-bromocarbonyls is presented. This method afforded the 2-alkynylaryl carbonyls, useful synthons for the accomplishment of many carbocyclic and heterocyclic motifs. Significantly, the strategy was extended to the one-pot synthesis of isobenzofurans via reduction followed by intramolecular 5- exo -dig cyclization.
- Krishna Reddy, Alavala Gopi,Satyanarayana, Gedu
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supporting information
p. 5149 - 5158
(2017/10/06)
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- Bioinspired Total Synthesis of (±)-Chaetophenol C Enabled by a Pd-Catalyzed Cascade Cyclization
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A novel Pd(II)-catalyzed cascade reaction has been developed that consists of a highly regio- and stereoselective oxa [4 + 2] cycloaddition reaction of o-alkynylbenzaldehydes and an intramolecular carboxylic group quenching of the in situ generated oxonium ion. This new reaction provides a one-step construction of the tetracyclic core structure of chaetophenol C from two simple starting materials. The developed chemistry was successfully applied to the first total synthesis of chaetophenol C and dozens of its analogues.
- Li, Yun,Zhang, Qingyu,Wang, Hongyu,Cheng, Bin,Zhai, Hongbin
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supporting information
p. 4387 - 4390
(2017/08/23)
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- TRACELESS DIRECTING GROUPS IN RADICAL CASCADES: FROM OLIGOALKYNES TO FUSED HELICENES WITHOUT TETHERED INITATORS
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The present disclosure is directed to a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by a propargyl alkoxy moiety. Radical translocations lead to the boomerang return of radical center to the site of initial attack where it assists to the elimination of the directing functionality via β-scission in the last step of the cascade. In some aspects, the reaction of the present invention is catalyzed by a stannane moiety, which allows further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions.
- -
-
Paragraph 0210
(2016/06/13)
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- Insights into the Gold-Catalyzed Propargyl Ester Rearrangement/Tandem Cyclization Sequence: Radical versus Gold Catalysis - Myers-Saito- versus Schmittel-Type Cyclization
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A detailed study of the gold-catalyzed tandem 1,3-carboxy migration/allene-enyne cycloisomerization was undertaken. It was found that after the initial allene formation the selectivity of the reaction is strongly influenced by the polarization of the remaining alkyne. Depending on the substitution pattern of the starting diynes, either a Schmittel- or a Myers-Saito-type cyclization was triggered. The 6-endo-dig Myers-Saito-type cyclization gave access to benzo[b]fluorenes, while the Schmittel pathway (5-exo-dig) delivered benzofulvenes as final products. In special cases a yet unknown pathway was opened by the ambiphilic nature of the allene moiety. In these cases completely different products were obtained by the nucleophilic attack of the alkyne moiety onto the allene that can also act as an electrophile. Mechanistic studies revealed that diradical pathways can be ruled out for this type of tandem cyclization reactions and it is shown that both steps of the reaction cascade are catalyzed by the gold complex.
- Rettenmeier, Eva,Hansmann, Max M.,Ahrens, Alexander,Rübenacker, Katharina,Saboo, Tapish,Massholder, Joy,Meier, Christian,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 14401 - 14409
(2015/10/05)
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- Regioselective Synthesis of Polyheterohalogenated Naphthalenes via the Benzannulation of Haloalkynes
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Independent control of halide substitution at six of the seven naphthalene positions of 2-arylnaphthalenes is achieved through the regioselective benzannulation of chloro-, bromo-, and iodoalkynes. The modularity of this approach is demonstrated through the preparation of 44 polyheterohalogenated naphthalene products, most of which are difficult to access through known naphthalene syntheses. The outstanding regioselectivity of the reaction is both predictable and proven unambiguously by single-crystal X-ray diffraction for many examples. This synthetic method enables the rapid preparation of complex aromatic systems poised for further derivatization using established cross-coupling methods. The power and versatility of this approach makes substituted naphthalenes highly attractive building blocks for new organic materials and diversity-oriented synthesis.
- Lehnherr, Dan,Alzola, Joaquin M.,Lobkovsky, Emil B.,Dichtel, William R.
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supporting information
p. 18122 - 18127
(2015/12/24)
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- Traceless directing groups in radical cascades: From oligoalkynes to fused helicenes without tethered initiators
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We report the first example of a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by propargyl OR moiety. Radical translocations lead to the boomerang return of the radical center to the site of initial attack where it assists the elimination of the directing functionality via β-scission in the last step of the cascade. The Bu3Sn moiety continues further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions. (Chemical Equation Presented).
- Pati, Kamalkishore,Gomes, Gabriel Dos Passos,Harris, Trevor,Hughes, Audrey,Phan, Hoa,Banerjee, Tanmay,Hanson, Kenneth,Alabugin, Igor V.
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supporting information
p. 1165 - 1180
(2015/02/05)
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- Expedient Iodocyclization Approach Toward Polysubstituted 3H-Benzo[e]indoles
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A facile and expedient iodocyclization of 4-(2-prop-1-ynylphenyl)-1H-pyrroles towards the synthesis of polysubstituted 3H-benzo[e]indoles is reported. The transformation was optimized and the best results were obtained by using iodine (1.2 equiv,) in dichloromethane, and potassium carbonate as base. The starting 1,2,3,4-tetrasubstituted pyrroles were efficiently obtained by means of a nickel(II) chloride-promoted four-component (nitromethane, amine, 2-alkynylbenzaldehyde and ethyl acetoacetate) reaction. Further functionalization of the resulting 5-iodoheterocycles was also explored.
- Martins, Guilherme M.,Zeni, Gilson,Back, Davi F.,Kaufman, Teodoro S.,Silveira, Claudio C.
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supporting information
p. 3255 - 3261
(2015/11/03)
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- Copper(ii)-catalyzed cascade approach for the synthesis of pyrrolo[2,1-f][1,2,4]triazine-fused isoquinolines
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We report herein a one-pot copper(ii)-catalyzed coupling-cyclization leading to small molecules based on a novel structural motif, i.e. the pyrrolo[2,1-f][1,2,4]triazine moiety fused with an isoquinoline ring. The reaction is easy to perform in good to excellent yields with high atom economy and exhibits a broad substrate scope.
- Chen, Jianyang,Liu, Bo,Chen, Yanhong,He, Qian,Yang, Chunhao
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p. 11168 - 11175
(2014/03/21)
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- Synthesis of naphthalene derivatives from ortho -alkynylacetophenone derivatives via tandem in situ incorporation of acetal and intramolecular heteroalkyne metathesis/annulation
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An interesting domino reaction for the synthesis of substituted naphthyl ketones has been developed using readily accessible starting materials. This domino reaction proceeds via in situ incorporation of an acetal followed by intramolecular heteroalkyne metathesis/annulation in an ortho- alkynylacetophenone derivative. A deuterium incorporation experiment has been carried out to understand the mechanism.
- Manojveer, Seetharaman,Balamurugan, Rengarajan
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supporting information
p. 1712 - 1715
(2014/04/17)
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- Exo-dig radical cascades of skipped enediynes: Building a naphthalene moiety within a polycyclic framework
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Cascade radical transformations of acyclic precursors open efficient, convenient and atom-economical access to functionalized compounds of increased structural complexity. This report describes a selective sequence of 5-exo-dig and 6-exo-dig cyclizations followed by attack at a pendant aromatic moiety and rearomatization.
- Pati, Kamalkishore,Hughes, Audrey M.,Phan, Hoa,Alabugin, Igor V.
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supporting information
p. 390 - 393
(2014/04/03)
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- Au(i)-catalyzed triple bond alkoxylation/dienolether aromaticity-driven cascade cyclization to naphthalenes
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A novel strategy for the synthesis of multisubstituted naphthalenes was developed via a Au(i)-catalyzed alkyne alkoxylation/dienolether aromaticity-driven cascade cyclization using 1,5-enyne substrates. The functional group toleration was examined by synthesizing a series of substrates and the mechanism was also studied based on intermediates isolated through deuterium labeling experiments. This journal is the Partner Organisations 2014.
- Liu, Yongxiang,Guo, Jia,Liu, Yang,Wang, Xiaoyu,Wang, Yanshi,Jia, Xinyu,Wei, Gaofei,Chen, Lizhu,Xiao, Jianyong,Cheng, Maosheng
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supporting information
p. 6243 - 6245
(2014/06/09)
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- Iodide-catalyzed halocyclization/cycloaddition/elimination cascade reaction
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An iodocyclization reaction of o-alkynylphenyl carboxaldehydes is reported that is truly catalytic with respect to the electrophilic iodine source. With a combination of tetrabutylammonium iodide (TBAI), Oxone as non-nucleophilic and easy to handle co-oxidant, and fluorinated protic solvents, highly substituted 1-naphthalenones could be prepared in high yields of up to 91%.
- Kloeckner, Ulrich,Finkbeiner, Peter,Nachtsheim, Boris J.
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p. 2751 - 2756
(2013/04/23)
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- Silver-catalyzed C-C bond formation with carbon dioxide: Significant synthesis of dihydroisobenzofurans
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The silver salt catalyzed the C-C bond forming reaction of o-alkynylacetophenone derivatives and carbon dioxide. In this reaction, a carbonyl group and a furan skeleton were successively constructed to afford the corresponding dihydroisobenzofuran derivatives.
- Sekine, Kohei,Takayanagi, Ayano,Kikuchi, Satoshi,Yamada, Tohru
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supporting information
p. 11320 - 11322
(2013/12/04)
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- Gold-catalyzed synthesis of dibenzopentalenes - Evidence for gold vinylidenes
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A series of easily accessible arene-1,2-diynes, bearing one aryl substituent on one of the alkynyl groups, is readily converted to dibenzopentalenes in good yields by gold(I) catalysts. The participation of gold acetylides could be proven by the direct conversion to the corresponding gem-diaurated dibenzopentalenes with a gold catalyst. From an experiment with a gold acetylide complex and stoichiometric amounts of the gold "catalyst" the corresponding gem-diaurated complex of a dibenzopentalene could be obtained and characterized by X-ray crystal structure analysis. Labelling studies with deuterated alkynes show the expected deuteration of the two remaining positions of the pentalene core. All this provides evidence for a dual activation mode of the reaction and gold(I) vinylidene complexes as intermediates of the catalytic cycle. Copyright
- Hashmi, A. Stephen K.,Wieteck, Marcel,Braun, Ingo,Noesel, Pascal,Jongbloed, Linda,Rudolph, Matthias,Rominger, Frank
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supporting information; experimental part
p. 555 - 562
(2012/04/17)
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- Chiral counteranion-directed silver-catalyzed asymmetric synthesis of 1,2-dihydroisoquinolines by Friedel-Crafts alkylation reactions
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The reaction of ortho-alkynylaryl aldimines and indoles catalyzed by a silver binol-derived phosphate was realized to afford a series of enantioenriched 1,2-dihydroisoquinolines in moderate to good yields and ee. An interesting phenomenon that highly enantioenriched products could be obtained from their lower ee form by silica gel column chromatography was observed, providing an easy access to the enantiopure form of the product.
- Zhang, Jun-Wei,Xu, Zhe,Gu, Qing,Shi, Xiao-Xin,Leng, Xue-Bing,You, Shu-Li
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supporting information; experimental part
p. 5263 - 5268
(2012/08/08)
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- Palladium-catalyzed C-H oxidation of isoquinoline N-oxides: Selective alkylation with dialkyl sulfoxides and halogenation with dihalo sulfoxides
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A novel palladium-catalyzed C-H oxidation of isoquinoline N-oxides has been developed for regioselectively synthesizing substituted isoquinolines. The method represents the first example of using dialkyl sulfoxides as the alkyl sources for the construction of 1-alkylated isoquinolines. Moreover, the regioselective halogenation of isoquinoline N-oxides is also successful using dihalo sulfoxides as the halide sources. Copyright
- Yao, Bo,Song, Ren-Jie,Liu, Yan,Xie, Ye-Xiang,Li, Jin-Heng,Wang, Meng-Ke,Tang, Ri-Yuan,Zhang, Xing-Guo,Deng, Chen-Liang
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supporting information; scheme or table
p. 1890 - 1896
(2012/09/22)
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- Rapid access to benzo-annelated heterocycles, naphthalenes, and polysubstituted benzenes through a novel benzannulation reaction
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A novel, efficient, and powerful methyl mercaptoacetate triggered benzannulation reaction is described. The precursors are heterocyclic, aromatic or acyclic compounds bearing a carbonyl group at ortho position to an internal alkyne. The methodology does not require transition-metal catalysts and moreover it is general for the preparation of wide range of benzo-annelated heterocycles, naphthalenes and benzenes.
- Cikotiene, Inga,Buksnaitiene, Rita,Sazinas, Rokas
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experimental part
p. 706 - 717
(2011/03/19)
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- NHC-catalyzed oxidative cyclization reactions of 2-alkynylbenzaldehydes under aerobic conditions: Synthesis of O-Heterocycles
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Chemical equations presented. An NHC-catalyzed, regio- and stereoselective oxidative cyclization of o-alkynylbenzaldehydes bearing an unactivated alkyne moiety as an internal electrophile has been developed to afford phthalides and isocoumarins. A single organocatalytic system enabled two sequential C-O bond formations to take place in an atom economical manner via highly efficient dual activation. Molecular oxygen in air could be utilized as a source of an oxygen atom for the oxidation of aldehydes to the corresponding benzoic acids under our newly developed reagent system.
- Park, Jong Hyub,Bhilare, Sachin V.,Youn, So Won
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supporting information; experimental part
p. 2228 - 2231
(2011/07/09)
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- Gold-catalyzed cascade friedel-crafts/furan-yne cyclization/heteroenyne metathesis for the highly efficient construction of phenanthrene derivatives
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A rapid access to highly substituted phenanthrenyl ketones through gold-catalyzed cyclization of 1,6-diyn-4-en-3-ols with furans has been developed. Gold catalysts are effective to catalyze three cascade processes involving Friedel-Crafts/furan-yne cyclization/heteroenyne metathesis through C-O bond and alkyne activation. This method offers several advantages such as high selectivities and easily accessible starting materials.
- Chen, Yifeng,Li, Guijie,Liu, Yuanhong
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supporting information; experimental part
p. 392 - 400
(2011/04/22)
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- Rapid access to 1-methyleneindenes via palladium-catalyzed tandem reactions of 1-(2,2-dibromovinyl)-2-alkynylbenzenes with arylboronic acids
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A novel and efficient route for the synthesis of 1-methyleneindenes via palladium-catalyzed tandem reactions of 1-(2,2-dibromovinyl)-2-alkynylbenzene with arylboronic acids is described. This reaction proceeded under mild conditions with high efficiency and excellent selectivity. The Royal Society of Chemistry 2010.
- Ye, Shengqing,Yang, Xiaodi,Wu, Jie
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supporting information; scheme or table
p. 2950 - 2952
(2010/08/05)
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- Synthesis of 4-(1-alkenyl)isoquinolines by palladium(II)-catalyzed cyclization/olefination
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A variety of 4-(1-alkenyl)-3-arylisoquinolines have been prepared in moderate to excellent yields by the Pd(II)-catalyzed cyclization of 2-(1-alkynyl)arylaldimines in the presence of various alkenes. The introduction of an o-methoxy group on the arylaldimine promotes the Pd-catalyzed cyclization and stabilizes the resulting Pd(II) intermediate, improving the yields of the isoquinoline products. Ketone-containing isoquinolines 36 and 49-51 have also been prepared by this process when unsaturated alcohols are employed as the alkenes.
- Huang, Qinhua,Larock, Richard C.
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p. 980 - 988
(2007/10/03)
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- CONDENSED HETEROAROMATIC RING SYSTEMS. XI. A FACILE SYNTHESIS OF ISOQUINOLINE N-OXIDES
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Isoquinoline 2-oxides (5a-f) were obtained by the cyclization of 2-ethynylbenzaldehyde oxime (4a-f) under basic conditions.The starting compounds (4a-f) were easily synthesized by the palladium-catalyzed reaction of 2-bromobenzaldehydes (1 and 2) with terminal acetylenes, and subsequent oximation of the resulting 2-ethynylbenzaldehydes (3a-f).
- Sakamoto, Takao,Kondo, Yoshinori,Miura, Norio,Hayashi, Kazuhiko,Yamanaka, Hiroshi
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p. 2311 - 2314
(2007/10/02)
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