- Enantioselective Dearomative [3 + 2] Umpolung Annulation of N-Heteroarenes with Alkynes
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Enantioselective [3 + 2] annulation of N-heteroarenes with alkynes has been developed via a cobalt-catalyzed dearomative umpolung strategy in the presence of chiral ligand and reducing reagent. A variety of electron-deficient N-heteroarenes, including qui
- Cui, Bing-Hui,Huang, Wen-Yu,Jia, Yi-Xia,Liang, Ren-Xiao,Liu, Hang,Liu, Jia-Liang,Wang, Qiang,Yang, Peng,Zhang, Xiao-Dong,Zhang, Yue-Yuan
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supporting information
p. 1087 - 1093
(2022/02/09)
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- Lipshutz-type bis(amido)argentates for directed: Ortho argentation
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Bis(amido)argentate (TMP)2Ag(CN)Li2 (3, TMP-Ag-ate; TMP = 2,2,6,6-tetramethylpiperidido) was designed as a tool for chemoselective aromatic functionalization via unprecedented directed ortho argentation (DoAg). X-Ray crystallographic analysis showed that 3 takes a structure analogous to that of the corresponding Lipshutz cuprate. DoAg with this TMP-Ag-ate afforded multifunctional aromatics in high yields in processes that exhibited high chemoselectivity and compatibility with a wide range of functional groups. These included organometallics- A nd transition metal-susceptible substituents such as methyl ester, aldehyde, vinyl, iodo, (trifluoromethanesulfonyl)oxy and nitro groups. The arylargentates displayed good reactivity with various electrophiles. Chalcogen (S, Se, and Te) installation and azo coupling reactions also proceeded efficiently.
- Tezuka, Noriyuki,Hirano, Keiichi,Peel, Andrew J.,Wheatley, Andrew E. H.,Miyamoto, Kazunori,Uchiyama, Masanobu
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p. 1855 - 1861
(2020/03/03)
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- An Unprecedented, Lewis Acid-Mediated, Metal-Free Iodoannulation Strategy to Aromatic Iodides
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A direct transformation of ortho-alkynylated aromatic vinyl ethers to 1-iodonaphthalenes and other iodo-heterocycles under mild Lewis acidic conditions in the presence of iodide as an external nucleophile is reported. The first example of an iodoannulation strategy using a nucleophilic source of iodine, coupled with good to excellent yields, exclusive alpha regioselectivity and a broad substrate scope makes this work an attractive avenue towards the construction of aromatic iodides.
- Banik, Trisha,Betkekar, Vipul V.,Kaliappan, Krishna P.
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supporting information
p. 3676 - 3680
(2018/10/31)
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- Direct conversion of 1-(2-bromobenzoyl)isoquinolines to dibenzo[ de,g ]quinolin-7-ones via reductive photocyclization
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A series of A/D-ring substituted dibenzo[de,g]quinolin-7-ones was produced from the corresponding isoquinolinones and (2-bromophenyl)acetonitriles in four steps. This represents a convenient approach toward the synthesis of tetracyclic alkaloids. A direct conversion of 1-(2-bromobenzoyl)isoquinolines to dibenzo[de,g]quinolin-7-ones is the key step in the total synthesis. The yield of the reductive photocyclization depends on the position of the substituents at the isoquinolyl ring and the phenyl group. The mechanism of the reductive photocyclization is also discussed.
- Chuang, Ta-Hsien,Li, Chien-Fu,Lee, Hong-Zin,Wen, Yu-Chia
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p. 4974 - 4984
(2013/06/27)
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- Computed CH acidity of biaryl compounds and their deprotonative metalation by using a mixed lithium/Zinc-TMP base
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With the aim of synthesizing biaryl compounds, several aromatic iodides were prepared by the deprotonative metalation of methoxybenzenes, 3-substituted naphthalenes, isoquinoline, and methoxypyridines by using a mixed lithium/zinc-TMP (TMP=2,2,6,6-tetramethylpiperidino) base and subsequent iodolysis. The halides thus obtained, as well as commercial compounds, were cross-coupled under palladium catalysis (e.g., Suzuki coupling with 2,4-dimethoxy-5-pyrimidylboronic acid) to afford various representative biaryl compounds. Deprotometalation of the latter compounds was performed by using the lithium/zinc-TMP base and evaluated by subsequent iodolysis. The outcome of these reactions has been discussed in light of the CH acidities of these substrates, as determined in THF solution by using the DFT B3LYP method. Except for in the presence of decidedly lower pKa values, the regioselectivities of the deprotometalation reactions tend to be governed by nearby coordinating atoms rather than by site acidities. In particular, azine and diazine nitrogen atoms have been shown to be efficient in inducing the reactions with the lithium/zinc-TMP base at adjacent sites (e.g., by using 1-(2-methoxyphenyl)isoquinoline, 4-(2,5-dimethoxyphenyl)-3-methoxypyridine, or 5-(2,5-dimethoxyphenyl)-2,4-dimethoxypyrimidine as the substrate), a behavior that has already been observed upon treatment with lithium amides under kinetic conditions. Finally, the iodinated biaryl derivatives were involved in palladium-catalyzed reactions. Copyright
- Kadiyala, Raghu Ram,Tilly, David,Nagaradja, Elisabeth,Roisnel, Thierry,Matulis, Vadim E.,Ivashkevich, Oleg A.,Halauko, Yury S.,Chevallier, Floris,Gros, Philippe C.,Mongin, Florence
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supporting information
p. 7944 - 7960
(2013/07/05)
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- Preparation of polyfunctional zinc organometallics using an Fe- or Co-catalyzed Cl/Zn-exchange
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A new Fe- or Co-catalyzed Cl/Zn-exchange reaction allows the direct transformation of aryl, heteroaryl, and also alkyl chlorides into the corresponding zinc reagents. The method tolerates functional groups such as a nitrile or an ester. Remarkably, secondary and tertiary alkyl chlorides are suitable substrates for the Cl/Zn exchange.
- Melzig, Laurin,Diene, Coura R.,Rohbogner, Christoph J.,Knochel, Paul
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supporting information; experimental part
p. 3174 - 3177
(2011/08/06)
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- Scaleable preparation of functionalized organometallics via directed ortho metalation using Mg- and Zn-amide bases
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A range of aryl and heteroaryl organometallics are efficiently prepared in THF Wia directed ortho metalation by using the previously reported amide bases tmpMgCl · LiCl (tmp ) 2,2,6,6-tetramethylpiperidyl), tmp2Mg · 2LiCl and tmp2Zn
- Knochel, Paul,Wunderlich, Stefan H.,Rohbogner, Christoph J.,Unsinn, Andreas
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experimental part
p. 339 - 345
(2011/03/21)
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- One-pot iodination of hydroxypyridines
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(Chemical Equation Presented) A one-pot, high-yielding iodination of hydroxypyridines and hydroxyquinolines is described. The iodination proceeds under mild conditions, and the products are obtained in high yield without the need for chromatographic purif
- Maloney, Kevin M.,Nwakpuda, Emily,Kuethe, Jeffrey T.,Yin, Jingjun
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supporting information; experimental part
p. 5111 - 5114
(2009/10/24)
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- Controlling axial conformation in 2-Arylpyridines and 1-Arylisoquinolines: Application to the asymmetric synthesis of QUINAP by dynamic thermodynamic resolution
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Unlike related biphenyl compounds, 2-arylpyridines and 1-arylisoquinolines can be induced to adopt preferentially one of two axial conformationsby the presence of a sulfinyl substituent adjacent to the Ar-Ar bond. I n the case of more substituted biaryls,
- Clayden, Jonathan,Fletcher, Stephen P.,McDouall, Joseph J. W.,Rowbottom, Stephen J. M.
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supporting information; experimental part
p. 5331 - 5343
(2009/09/29)
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- Microwave-assisted trans-halogenation reactions of various chloro-, bromo-, trifluoromethanesulfonyloxy- and nonafluorobutanesulfonyloxy-substituted quinolines, isoquinolines, and pyridines leading to the corresponding iodinated heterocycles
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(Chemical Equation Presented) Microwave irradiation of certain chloro-, bromo-, trifluoromethanesulfonyloxy- and nonafluorobutanesulfonyloxy-substituted quinolines in the presence of acetic anhydride and sodium iodide leads, via a trans-halogenation process, to the corresponding iodides in high yield. Related conversions involving pyridines and isoquinolines can also be achieved under similar conditions.
- Bissember, Alex C.,Banwell, Martin G.
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supporting information; experimental part
p. 4893 - 4895
(2009/10/02)
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- PREPARATION AND USE OF MAGNESIUM AMIDES
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The present application relates to mixed Mg/Li amides of the general formula R1R2N-Mg-NR3R4.zLiY (II) wherein R1, R2, R3, and R4 are, independently, selected from H, substituted or unsubstituted aryl or heteroaryl containing one or more heteroatoms, linear, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, alkynyl, or silyl derivatives thereof; and R1 and R2 together, or R3 and R4 together can be part of a cyclic or polymeric structure; and wherein at least one of R1 and R2 and at least one of R3 and R4 is other than H; Y is selected from the group consisting of F; Cl; Br; I; CN; SCN; NCO; HaIOn, wherein n = 3 or 4 and Hal is selected from Ci, Br and I; NO3; BF4; PF6; H; a carboxylate of the general formula RxCO2; an alcoholate of the general formula ORx; a thiolate of the general formula SRx; RxP(O)O2; or SCORx; or SCSRx; OnSRx, wherein n = 2 or 3; or NOn, wherein n = 2 or 3; and a derivative thereof; wherein Rx is a substituted or unsubstituted aryl or heteroaryl containing one or more heteroatoms, linear, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, alkynyl, or derivatives thereof, or H; m is O or 1; and z > 1; as well as a process for the preparation of the mixed Mg/Li amides and the use of these amides, e.g. as bases.
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Page/Page column 25-27
(2008/12/07)
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- Preparation and use of magnesium amides
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The present application relates to mixed Mg/Li amides of the general formula ???????? R1R2N-MgX·zLiY?????(I), wherein R1, R2 and R3 independently are selected from substituted or unsubstituted aryl or heteroaryl containing one or more heteroatoms, linear, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, alkynyl, or derivatives thereof, and, for R1 and R2 only, the silyl derivatives thereof; one of R1 and R2 may be H; or R1 and R2 together can be part of a cyclic or polymeric structure; X and Y independently are selected amongst others from the group consisting of F; Cl; Br; I; CN; SCN; NCO; and z > 0, as well as a process for the preparation of the mixed Mg/Li amides and the use of these amides, e.g. as bases.
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Page/Page column 4; 7-8
(2008/06/13)
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- Mixed Mg/Li amides of the type R2NMgCl·LiCl as highly efficient bases for the regioselective generation of functionalized aryl and heteroaryl magnesium compounds
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(Chemical Equation Presented) Two are better than one: Mixed lithium-magnesium complexes of the type R2NMgCl·LiCl are kinetically highly active bases that convert a range of polyfunctional aromatic and heteroaromatic substrates into the corresponding magnesiated derivatives with high regioselectivity.
- Krasovskiy, Arkady,Krasovskaya, Valeria,Knochel, Paul
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p. 2958 - 2961
(2007/10/03)
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- Acid-Mediated Halogen Exchange in Heterocyclic Arenes: A Highly Effective Iodination Method
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Heterocyclic arenes including pyridyl, quinolyl, and isoquinolyl chlorides have been converted to their corresponding iodides in good to high yields via acid-mediated nucleophilic halogen exchange with sodium iodide. This procedure avoids the use of transition metals, harsh reaction conditions, and affords highly regioselective halide exchange. Chloride substituents in position 2 and 4 of pyridines and quinolines are readily substituted by iodide in 75-91% and conversion of 1-chloroisoquinoline to its iodide derivative was found to proceed with 90% yield. Positions that are not activated for nucleophilic aromatic substitution proved to be inert to halide exchange. Regioselective chloride/iodide exchange in 4,7-dichloroquinoline hydrochloride gave 7-chloro-4-iodoquinoline, an important precursor of anti-malaria drugs, in almost 90% yield.
- Wolf, Christian,Tumambac, Gilbert E.,Villalobos, Cristina N.
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p. 1801 - 1804
(2007/10/03)
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- Silyl-mediated halogen/halogen displacement in pyridines and other heterocycles
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Heating with bromotrimethylsilane converts 2-chloropyridine into 2-bromopyridine and 2-chloro-6-methylpyridine into 2-bromo-6-methylpyridine. Both 2-chloropyridines and 2-bromopyridines give the corresponding iodo compound when treated with in situ generated iodotrimethylsilane. Although 3- and 4-chloropyridine are completely inert, 2,4-dichloropyridine undergoes the halogen/halogen exchange simultaneously at the 2- and 4-position. Halogen displacement takes place exclusively at the 2-position with 2,3-dichloropyridine and 2,5-dichloropyridine. In agreement with the intermediacy of N-trimethylsilylpyridinium salts as a prerequisite for the occurrence of halogen exchange, neither 2-fluoropyridine and 2-fluoro-6-methylpyridine nor any 2,6-dihalopyridine reacts. Finally, bromine/chlorine and iodine/chlorine substitution can also be accomplished with 2-or 4-chloroquinoline, 1-chloroisoquinoline, 2-chloropyrimidine, chloropyrazine and 2,3-dichloroquinoxaline as substrates. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002).
- Schlosser, Manfred,Cottet, Fabrice
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p. 4181 - 4184
(2007/10/03)
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- Studies on Organometallic Compounds. II. Facile and Convenient Method for the Synthesis of Idoazines through Iododestannation of Trimethylstannylazines
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Trimethylsatannyl and bis(trimethylstannyl) derivatives of pyridine, quinoline, and isoquinoline were prepared from the corresponding halo and dihalo (chloro or bromo) derivatives and trimethylstannyl sodium, which was generated in situ from chlorotrimethylsatannane and sodium.These stannyl derivatives readily underwent iododestannation on treatment with iodine to produce the corresponding iodo and diiodo derivatives of pyridine, quinoline, and isoquinoline, respectively, in good yields.Keywords -trimethylsannylazine; bis(trimethylstannyl)azine; iodoazine; diiodoazine; iododestannation; trimethylstannyl sodium; chlorotrimethylstannane
- Yamamoto, Yukata,Yanagi, Akihiko
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p. 1731 - 1737
(2007/10/02)
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