- A ONE-POT ORTHO ALKYLATION OF AROMATIC ALDEHYDES
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The addition of aromatic aldehydes to lithium N-methylpiperazide in benzene gave α-amino alkoxides which were ortho-lithiated with excess n-butyllithium.Subsequent alkylation and hydrolysis provided ortho-substituted aromatic aldehydes via a one-pot reaction.
- Comins, Daniel L.,Brown, Jack D.,Mantlo, Nathan B.
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- Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes
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A sequential one-pot process for chemoselectively reducing sterically demanding N,N-diisopropylamides to aldehydes has been developed. In this reaction, amides are activated with EtOTf to form imidates, which are reduced with LiAlH(OR)3 [R = t-Bu, Et] to give aldehydes by hydrolysis of the resulting hemiaminals. The non-nucleophilic base 2,6-DTBMP remarkably improves reaction efficiency. The combination of EtOTf/2,6-DTBMP and LiAlH(O-t-Bu)3 was found to be optimal for reducing alkyl, alkenyl, alkynyl, and 2-monosubstituted aryl N,N-diisopropylamides. In contrast, EtOTf and LiAlH(OEt)3 in the absence of base were found to be optimal for reducing extremely sterically demanding 2,6-disubstituted N,N-diisopropylbenzamides. The reaction tolerates various reducible functional groups, including aldehyde and ketone. 1H NMR studies confirmed the formation of imidates stable in water. The synthetic usefulness of this methodology was demonstrated with N,N-diisopropylamide-directed ortho-metalation and C-H bond activation.
- Xiao, Peihong,Tang, Zhixing,Wang, Kai,Chen, Hua,Guo, Qianyou,Chu, Yang,Gao, Lu,Song, Zhenlei
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p. 1687 - 1700
(2018/02/23)
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- Internal Lewis acid assisted ureas: Tunable hydrogen bond donor catalysts
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The strategic incorporation of internal Lewis acids onto urea scaffolds gives rise to a family of tunable hydrogen bond donor catalysts. The nature of the Lewis acid and associated ligands affects the urea polarization, acidity, and activity in reactions
- Nickerson, David M.,Angeles, Veronica V.,Auvil, Tyler J.,So, Sonia S.,Mattson, Anita E.
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supporting information
p. 4289 - 4291
(2013/06/04)
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- Boronate urea activation of nitrocyclopropane carboxylates
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Boronate ureas operate as catalysts for the activation of nitrocyclopropane carboxylates in nucleophilic ring-opening reactions. A variety of amines were found to open the urea-activated nitrocyclopropane carboxylates, generating highly useful nitro ester
- So, Sonia S.,Auvil, Tyler J.,Garza, Victoria J.,Mattson, Anita E.
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supporting information; experimental part
p. 444 - 447
(2012/03/10)
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- Internal Lewis acid assisted benzoic acid catalysis
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Internal Lewis acid assisted benzoic acid derivatives are introduced as new low-molecular-weight single-hydrogen-bond donor catalysts for the activation of nitroalkenes. Selected 2-borylbenzoic acid derivatives gave good yields of products in the addition of indoles to nitroalkenes. Control experiments suggest that both the internal Lewis acid coordination and the carboxylic acid functionalities are critical to the optimal performance of these catalysts. Georg Thieme Verlag Stuttgart New York.
- Auvil, Tyler J.,Mattson, Anita E.
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supporting information; experimental part
p. 2173 - 2180
(2012/09/22)
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- Internal lewis acid assisted hydrogen bond donor catalysis
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Boronate ureas are introduced as a new class of noncovalent catalysts for conjugate addition reactions with enhanced activity. Through intramolecular coordination of the urea functionality to a strategically placed Lewis acid, rate enhancements up to 10 t
- So, Sonia S.,Burkett, Julie A.,Mattson, Anita E.
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supporting information; experimental part
p. 716 - 719
(2011/04/24)
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- Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
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(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
- Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
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supporting information; scheme or table
p. 4447 - 4450
(2010/08/19)
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- Synthesis and properties of nucleoside derivatives acylated by chemically stable 2-(trimethylsilyl)benzoyl group
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We report the synthesis and properties of nucleoside derivatives acylated by 2-(trimethylsilyl)benzoyl (TMSBz) that proved to be extremely stable under basic conditions when introduced into the 5′-hydroxyl group of thymidine, the 4-amino group of deoxycyt
- Yamada, Ken,Taguchi, Haruhiko,Ohkubo, Akihiro,Seio, Kohji,Sekine, Mitsuo
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experimental part
p. 5928 - 5932
(2009/12/26)
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- Copper(I) tert-butoxide-promoted coupling of o-(1-hydroxyalkyl)arylsilanes with organic halides
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Copper(I) tert-butoxide-promoted coupling of arylsilanes possessing a 1-hydroxyalkyl group at the o-position with organic halides proceeded to give disubstituted arenes. The results indicate that an intermediary arylcopper species is formed by aromatic Csp2-to-O silyl migration.
- Taguchi, Haruhiko,Takami, Kazuto,Tsubouchi, Akira,Takeda, Takeshi
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p. 429 - 432
(2007/10/03)
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- A novel method for the synthesis of regiospecifically sulfonated porphyrin monomers and dimers
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A novel method has been developed to regiospecifically synthesize water-soluble sulfonated porphyrin monomers tetrakis(4′-sulfonatophenyl)porphyrin, tetrakis(3′-sulfonatophenyl)porphyrin, tetrakis(2′-sulfonatophenyl)porphyrin, tetrakis(2′,5′-dimethyl-4′-sulfonatophenyl)porphyrin, the dimers of 1,2-bis[5,10,15-tri(4′-sulfonatophenyl)porphyrinyl]benzene and 1,2-bis[5,10,15-tri(2′,5′-dimethyl-4′-sulfonatophenyl) porphyrinyl]benzene in high yields through introduction of the trimethylsilyl group on the phenyl rings and reaction with trimethylsilyl chlorosulfonate in CCl4 solvent.
- Ye, Bao-Hui,Naruta, Yosinori
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p. 3593 - 3601
(2007/10/03)
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- Photochemical and acid-catalyzed rearrangements of 4-carbomethoxy-4-methyl-3-(trimethylsilyl)-2,5-cyclohexadien-1-one
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The synthesis of 4-carbomethoxy-4-methyl-3-(trimethylsilyl)-2,5-cyclohexadien-1-one (1) in 60% overall yield from benzaldehyde is described. Irradiation (366 nm) of 1 in benzene solution gave products of type A photorearrangement; e.g., diastereomers of the 4-(trimethylsilyl)- and 5-(trimethylsilyl)bicyclo[3.1.0]hex-3-en-2-ones 8 and 9. Bicyclohexenones 9a and 9b could not be isolated, but underwent acid-catalyzed protiodesilylative rearrangements on attempted chromatography (silica gel) to give a 1:1 mixture of (E)- and (Z)-4-(carbomethoxymethylmethylene)cyclopent-2-en-1-ones 12 and 13. Irradiation (366 nm) of either 12 or 13 resulted in photoisomerization to a photostationary state that was also a 1:1 mixture. Irradiation of 8a or 8b gave equivalent mixtures of phenols 14 and 15 by way of the type B oxyallyl zwitterion 17. The available experimental evidence suggests that both 9a and 9b undergo regiospecific photorearrangement to phenol 16 with no trace of 3-methyl-4-carbomethoxyphenol (19), the product of ipso substitution of the Me3Si group at C(4). Phenol 15 was isolated in 65% yield from the photoreaction of 1 in benzene with 20 equiv of CF3CO2H. The acid-catalyzed rearrangement of 1 to 3-carbomethoxy-4-methylphenol (21) occurs in 91% yield by way of CO2Me group rearrangement to C(3) to give the Me3Si-stabilized carbocation 23.
- Schultz, Arthur G.,Antoulinakis, Evan G.
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p. 4555 - 4559
(2007/10/03)
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- Ortho Metalation Directed by α-Amino Alkoxides
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The addition of aromatic aldehydes to certain lithium dialkylamides in benzene or tetrahydrofuran gave α-amino alkoxides which were ortho lithiated with excess n-butyllithium.Subsequent alkylation and hydrolysis provided ortho-substituted aromatic aldehydes via a one-pot reaction.The ortho metalation of α-amino alkoxides derived from 1- and 2-naphthaldehyde and various substituted benzaldehydes was examined.When N,N,N'-trimethylethylenediamine was used as the amine component of the α-amino alkoxide, metalation could be carried out at lower temperatures.This rate increase is due to an intramolecular TMEDA-like assisted metalation.The synthetic utility of this ortho metalation, including how varying the amine component of the α-amino alkoxide affects the regiochemistry and metalation rate, is discussed.
- Comins, Daniel L.,Brown, Jack D.
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p. 1078 - 1083
(2007/10/02)
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- ORTHO METALATION DIRECTED BY α-AMINO ALKOXIDES. AN IMPROVED SYNTHESIS OF ORTHO-SUBSTITUTED ARYL KETONES
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Ortho-substituted aryl ketones are prepared from N--N-methylbenzamides via ortho lithiation of intermediate α-amino alkoxides, formed in situ by addition of RLi.An ortho lithiation of N--N-methylbenzamide is also described.
- Comins, Daniel L.,Brown, Jack D.
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p. 5465 - 5468
(2007/10/02)
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