- Synthesis of N-heterocyclic carbene-Pd(II)-5-phenyloxazole complexes and initial studies of their catalytic activity toward the Buchwald-Hartwig amination of aryl chlorides
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Three new N-heterocyclic carbene (NHC)-Pd(II) complexes using 5-phenyloxazole as the ancillary ligand have been obtained in moderate to good yields by a one-pot reaction of the corresponding imidazolium salts, palladium chloride and 5-phenyloxazole under mild conditions. Initial studies showed that one of the complexes is an efficient catalyst for the Buchwald-Hartwig amination of aryl chlorides with various secondary and primary amines under the varied catalyst loading of 0.01-0.05 mol%, thus it will enrich the chemistry of NHCs and give an alternative catalyst for the coupling of challenging while cost-low aryl chlorides.
- Zhang, Zhi-Mao,Xu, Yu-Ting,Shao, Li-Xiong
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- Dialkylterphenyl Phosphine-Based Palladium Precatalysts for Efficient Aryl Amination of N-Nucleophiles
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A series of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR2Ar′ (R=Me, Et, iPr, Cyp (cyclopentyl), Ar′=ArDipp2, ArXyl2f, Dipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl=xylyl) have been prepared and structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e., Me and Et substituents) whereas the largest phosphines provided cationic palladacycles in which the phosphines adopted a bidentate hemilabile k1-P,η1-Carene coordination mode. The influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl amination reactions. Cationic complexes bearing the phosphines PiPr2ArXyl2 and PCyp2ArXyl2 were the most active of the series. These precatalysts have demonstrated a high versatility and efficiency in the coupling of a variety of nitrogen nucleophiles, including secondary amines, alkyl amines, anilines, and indoles, with electronically deactivated and ortho-substituted aryl chlorides at low catalyst loadings (0.25–0.75 mol % Pd) and without excess ligand.
- Rama, Raquel J.,Maya, Celia,Nicasio, M. Carmen
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supporting information
p. 1064 - 1073
(2020/01/25)
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- Tropane alkaloid compounds and method of manufacturing using sequential oxidation reactions
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The present invention relates to a tropane alkaloid compound sequentially using an oxidative Mannich ring reaction and a method for producing the same. The present invention provides a tropane alkaloid compound having a structure of chemical formula 1 in
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Paragraph 0098; 0110-0114
(2020/06/16)
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- Visible-Light-Enabled Direct Decarboxylative N-Alkylation
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The development of efficient and selective C?N bond-forming reactions from abundant feedstock chemicals remains a central theme in organic chemistry owing to the key roles of amines in synthesis, drug discovery, and materials science. Herein, we present a dual catalytic system for the N-alkylation of diverse aromatic carbocyclic and heterocyclic amines directly with carboxylic acids, by-passing their preactivation as redox-active esters. The reaction, which is enabled by visible-light-driven, acridine-catalyzed decarboxylation, provides access to N-alkylated secondary and tertiary anilines and N-heterocycles. Additional examples, including double alkylation, the installation of metabolically robust deuterated methyl groups, and tandem ring formation, further demonstrate the potential of the direct decarboxylative alkylation (DDA) reaction.
- Arman, Hadi D.,Dang, Hang T.,Haug, Graham C.,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Vuong, Ngan T. H.
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supporting information
p. 7921 - 7927
(2020/04/10)
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- Phosphoryl chloride-mediated solvent-free synthesis of N-aryl-substituted azacycles from arylamines and cyclic ethers
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A solvent- and metal-free protocol for preparation of N-aryl substituted azacycles from arylamines and cyclic ethers is described. In this method, the combination of POCl3 and DBU is crucial for conversion of arylamines and cyclic ethers to five- and six-membered azacycles. Without solvent, a variety of N-aryl-substituted, five-membered azacycles (pyrrolidines, 2-methylpyrrolidines, and piperidine) and six-membered azacycles (isoindolines and tetrahydroisoquinolines) are synthesized in high yields. This green method provides a sustainable and efficient approach for the preparation of azacycles from various cyclic ethers.
- Tran, Van Hieu,La, Minh Thanh,Kim, Hee-Kwon
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supporting information
p. 1860 - 1863
(2019/06/19)
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- Metal-Free Synthesis of N-Aryl-Substituted Azacycles from Cyclic Ethers Using POCl3
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A facile method for the synthesis of N-aryl-substituted azacycles from arylamines and cyclic ethers has been developed. In this study, arylamines were treated with cyclic ethers in the presence of POCl3 and DBU to provide five- A nd six-membered azacycles. Using this method, various azacycloalkanes, isoindolines, and tetrahydroisoquinolines were prepared in high yields. This synthetic method offers an efficient approach to the production of azacycles from cyclic ethers.
- La, Minh Thanh,Kang, Soosung,Kim, Hee-Kwon
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p. 6689 - 6696
(2019/06/14)
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- N-Heterocyclic carbene-palladacyclic complexes: synthesis, characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01 mol%).
- Liu, Feng,Hu, Yuan-Yuan,Li, Di,Zhou, Quan,Lu, Jian-Mei
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p. 5683 - 5690
(2018/08/24)
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- N-heterocyclic carbene-palladium complex, and preparation method and application thereof
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The invention discloses an N-heterocyclic carbene-palladium complex, and a preparation method and application thereof. The N-heterocyclic carbene-palladium complex disclosed by the invention is shown in Formula (I), wherein L1 is a quinoline ligand or isoquinoline ligand, and N in the L1 is connected with Pd; L2 is an N-heterocyclic carbene ligand, and carbene carbon in the L2 is connected with the Pd; and X1 and X2 are respectively independently an anionic ligand. The N-heterocyclic carbene-palladium complex disclosed by the invention can efficiently catalyze carbon-carbon or carbon-heteroatom coupling reaction using aryl halide as a substrate. The formula is shown in the specification.
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Paragraph 0119; 0120; 0121; 0138; 0139
(2017/07/22)
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- Synthesis of N-heterocyclic carbene-Pd(II) complexes and their catalytic activity in the Buchwald-Hartwig amination of aryl chlorides
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Novel N-heterocyclic carbene-palladium(II) complexes using 2-picolinic acid as the ancillary ligand have been successfully developed under mild conditions. Their catalytic activity in organic synthesis has been initially tested in the Buchwald-Hartwig amination of secondary and primary amines with aryl chlorides. Various substituents on both substrates can be tolerated, giving the desired coupling products in good to almost quantitative yields. The minimum catalyst loading can be 0.01 mol%, implying their potential application toward industrial processes.
- Zhang, Zhi-Mao,Gao, Yu-Jue,Lu, Jian-Mei
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p. 7308 - 7314
(2017/12/01)
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- Organonickel complexes encumbering bis-imidazolylidene carbene ligands: Synthesis, X-ray structure and catalytic insights on Buchwald-Hartwig amination reactions
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New four coordinated homoleptic bis(diimidazolylidene)nickel(II) complexes (C1 & C2) were synthesized and characterized by elemental analysis, NMR (1H and13C) as well as ESI-Mass spectrometry. The molecular structure of the complex C1 was identified by means of single-crystal X-ray diffraction analysis, which revealed that the complexes possess a distorted square planar geometry with chelating bis(diimidazolylidene) NHC ligands and two non coordinating bromide counter ions in tetradentate C4fashion. A survey of their catalytic activity in Buchwald?Hartwig amination has been performed. The newly synthesized complexes also catalyzed the amination of aryl chlorides in the presence of KOtBu. Various aryl chlorides and amines can react smoothly to give the corresponding aminated products in moderate to high yields. The scope of the reaction encompasses electronically varied aryl chlorides and nitrogen-containing heteroaryl chlorides, including pyridine and quinoline derivatives. Both secondary and primary amines are well tolerated under the optimal reaction conditions.
- Nirmala, Muthukumaran,Saranya, Gandhi,Viswanathamurthi, Periasamy,Bertani, Roberta,Sgarbossa, Paolo,Malecki, Jan Grzegorz
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supporting information
p. 1 - 10
(2017/01/09)
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- Synthesis of Aminobenzopyranoxanthenes with Nitrogen-Containing Fused Rings
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An efficient and practical method for the synthesis of a variety of aminobenzopyranoxanthenes (ABPXs) with different nitrogen-containing fused rings was developed. On the basis of the mechanistic studies of the formation of the xanthene framework, the presented methodology was developed to facilitate access to previously inaccessible asymmetric ABPXs.
- Fukino, Natsumi,Kamino, Shinichiro,Takahashi, Minami,Sawada, Daisuke
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supporting information
p. 13626 - 13631
(2017/12/26)
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- Synthesis and characterization of N-heterocyclic carbene-palladium(II) chlorides-1-methylindazole and -1-methylpyrazole complexes and their catalytic activity toward C-N coupling of aryl chlorides
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A series of N-heterocyclic carbene-palladium(ii) chlorides-1-methylindazole and -1-methylpyrazole complexes was successfully synthesized and fully characterized by X-ray single crystal diffraction. In addition, initial investigations of their catalytic activity showed that they were efficient catalysts in the C-N coupling of primary and secondary amines with aryl chlorides at low catalyst loadings.
- Zhao, Xiao-Yun,Zhou, Quan,Lu, Jian-Mei
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p. 24484 - 24490
(2016/03/15)
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- Synthesis of N-heterocyclic carbene-PdCl2-(iso)quinoline complexes and their application in arylamination at low catalyst loadings
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A new type of N-heterocyclic carbene-PdCl2-(iso)quinoline complexes 3 were successfully achieved in acceptable to good yields from easily available starting materials under mild conditions, and their structures were unambiguously confirmed using X-ray single crystal diffraction. Furthermore, their catalytic activity toward Buchwald-Hartwig arylamination of aryl chlorides with primary and secondary amines was fully tested. Under the optimal reaction conditions, the expected arylated amines can be obtained in high to excellent yields at low catalyst loadings (0.005-0.05 mol%). It may be worth noting here that comparison of these complexes with other well-defined and easily available NHC-Pd(ii) complexes bearing different N-containing ancillary ligands was also carried out, showing their superior catalytic activity over all others.
- Liu, Feng,Zhu, Yi-Ran,Song, Lu-Gan,Lu, Jian-Mei
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p. 2563 - 2571
(2016/03/01)
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- Room-Temperature Practical Copper-Catalyzed Amination of Aryl Iodides
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An efficient and highly practical procedure is reported for the Ullmann-Goldberg-type copper-catalyzed amination of aryl iodides. By using a combination of copper iodide and proline in the presence of an excess of an amine, a wide range of aryl iodides can be readily aminated at room temperature. The reaction proceeds well regardless of the electronic properties of the starting aryl iodide and the amination products can be obtained without the need for purification by column chromatography in most cases. Owing to its efficiency and the mildness of the reaction conditions, this amination could also be extended to the amination of complex aryl iodides at room temperature.
- Deldaele, Christopher,Evano, Gwilherm
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p. 1319 - 1328
(2016/04/20)
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- Monocarboxylate transporter 1 inhibitors as potential anticancer agents
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Potent monocarboxylate transporter 1 inhibitors (MCT1) have been developed based on α-cyano-4-hydroxycinnamic acid template. Structure-activity relationship studies demonstrate that the introduction of p-N, N-dialkyl/diaryl, and o-methoxy groups into cyanocinnamic acid has maximal MCT1 inhibitory activity. Systemic toxicity studies in healthy ICR mice with few potent MCT1 inhibitors indicate normal body weight gains in treated animals. In vivo tumor growth inhibition studies in colorectal adenocarcinoma (WiDr cell line) in nude mice xenograft models establish that compound 27 exhibits single agent activity in inhibiting the tumor growth.
- Gurrapu, Shirisha,Jonnalagadda, Sravan K.,Alam, Mohammad A.,Nelson, Grady L.,Sneve, Mary G.,Drewes, Lester R.,Mereddy, Venkatram R.
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supporting information
p. 558 - 561
(2015/05/27)
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- N-(1-Oxy-2-picolyl)oxalamic Acid as an Efficient Ligand for Copper-Catalyzed Amination of Aryl Iodides at Room Temperature
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N-(1-Oxy-pyridin-2-ylmethyl)oxalamic acid was identified as efficient ligand for CuI-catalyzed amination of aryl halides at room temperature. In our catalytic system, N-arylation of cyclic secondary amines, primary amines, amino acids, and ammonia proceeded with moderate to excellent yields and high functional group tolerance.
- Wang, Yongbin,Ling, Jing,Zhang, Yu,Zhang, Ao,Yao, Qizheng
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p. 4153 - 4161
(2015/07/01)
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- Synthesis of N-aryl substituted, five- and six-membered azacycles using aluminum-amide complexes
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Synthesis of N-aryl substituted, five- and six-membered azacycloalkanes, isoindolines and tetrahydroisoquinolines, has been described. In this synthesis, cyclic ethers (n = 1, 2) were treated with dimethylaluminum-amide reagents, derived from a range of aryl amines and trimethylaluminum, to afford the corresponding azacycles in good yields. This journal is the Partner Organisations 2014.
- Korbad, Balaji L.,Lee, Sang-Hyeup
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supporting information
p. 8985 - 8988
(2014/08/05)
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- Synthesis of N-arylsubstituted pyrrolidines and piperidines by reaction of anilines with α,ω-diols catalyzed by FeCl3·6H2O in carbon tetrachloride
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N-Arylpyrrolidines and N-arylpiperidines were synthesized in 20-88% yields by the reaction of aniline and aniline derivatives with 1,4-butane- and 1,5-pentanediols in the presence of Fecontaining catalysts and carbon tetrachloride. 1,4-Butane- and 1,5-pentanediols are partially chlorinated under the reaction conditions to give chlorohydrins, which subsequently undergo Nheterocyclization with anilines to give N-arylpyrrolidines and N-arylpiperidines.
- Khusnutdinov, Ravil I.,Bayguzina, Alfiya R.,Asylbaeva, Rigina S.,Aminov, Rishat I.,Dzhemilev, Usein M.
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p. 341 - 350
(2014/12/12)
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- Cobalt-catalyzed electrophilic amination of arylzincs with N-chloroamines
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Roles reversed: An efficient cobalt-catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N-chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields. Copyright
- Qian, Xin,Yu, Zailu,Auffrant, Audrey,Gosmini, Corinne
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supporting information
p. 6225 - 6229
(2013/07/05)
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- Well-defined NHC-Pd(II)-Im (NHC=N-heterocyclic carbene; Im=1-methylimidazole) complexes catalyzed amination of aryl chlorides
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A new class of well-defined NHC-Pd(II)-Im complexes was synthesized and was found to be an efficient catalyst for the amination reactions of aryl chlorides. Under the optimal reaction conditions, a range of amines can be coupled to give the amination products in good to high yields.
- Zhu, Lei,Gao, Ting-Ting,Shao, Li-Xiong
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experimental part
p. 5150 - 5155
(2011/07/31)
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- Luminescent zinc salen complexes as single and two-photon fluorescence subcellular imaging probes
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A novel class of ZnSalens (ZnL1-10) with lipophilic and cationic conjugates as optical probes in single and two-photon fluorescence microscopy images of living cells were prepared, which exhibited chemo- and photostability, low cytotoxicity and high subcellular selectivity.
- Hai, Yang,Chen, Juan-Juan,Zhao, Pei,Lv, Hongbin,Yu, Yi,Xu, Pingyong,Zhang, Jun-Long
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supporting information; experimental part
p. 2435 - 2437
(2011/04/15)
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- Ligands for copper-catalyzed C-N bond forming reactions with 1 Mol% CuBr as catalyst
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Several new ligands were designed to promote copper-catalyzed Ullman C-N coupling reactions. In this group, 8-hydroxyquinolin-N-oxide was found to serve as a superior ligand for CuBr-catalyzed coupling reactions of aryl iodides, bromides, and chlorides with aliphatic amines and N-heterocycles under a low catalyst loading (1% [Cu] mol). Reactions with the inexpensive catalytic system display a high functional group tolerance as well as excellent chemoselectivity.
- Yang, Kai,Qiu, Yatao,Li, Zheng,Wang, Zhaoyang,Jiang, Sheng
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experimental part
p. 3151 - 3159
(2011/06/23)
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- Synthesis of a sensitive and selective potassium-sensing fluoroionophore
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"Chemical Equation Presented" An efficient synthesis is reported that delivers in 5 steps and 52% overall yield a new structurally simplified fluorescent K+ sensor with improved K+ sensitivity and selectivity over existing K+ sensors. The synthesis procedure utilizes a new template-directed oxidative C-N bond-forming macrocyclization reaction and reports new approaches to Pd(O), Sandmeyer-like and metal-free aminoarylations, as well as organotitanium additions to vinylogous sulfonates.
- Carpenter, Richard D.,Verkman
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supporting information; experimental part
p. 1160 - 1163
(2010/05/18)
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- Nickel-catalyzed amination of aryl tosylates
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(Chemical Equation Presented) The cross-coupling of aryl tosylates with amines and anilines was accomplished by using a Ni-based catalyst system from the combination of Ni(II)-(σ-aryl) complexes/N-heterocyclic carbenes (NHCs). The feature, scope, and limitation of this reaction are disclosed.
- Gao, Cai-Yan,Yang, Lian-Ming
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p. 1624 - 1627
(2008/09/17)
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- Synthesis and in vitro antiprotozoal activities of water-soluble, inexpensive 3,7-bis(dialkylamino)phenoxazin-5-ium derivatives
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3,7-Bis(dialkylamino)phenoxazinium salts were synthesized and evaluated for in vitro activities against Plasmodium falciparum, Trypanosoma cruzi, T. brucei rhodesiense, and Leishmania donovani. Notably, the compounds showed potent antiprotozoal activities, especially against P. falciparum and T. cruzi. The compounds with alkyl side chains less than three carbons in length possessed good activities with high selective indices.
- Ge, Jian-Feng,Arai, Chika,Kaiser, Marcel,Wittlin, Sergio,Brun, Reto,Ihara, Masataka
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scheme or table
p. 3654 - 3658
(2009/04/06)
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- Cadmium(II)-catalyzed C-N cross-coupling of amines with aryl iodides
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Cadmium diacetate dihydrate [Cd(OAc)2·2H2O] in combination with ethylene glycol catalyzes efficiently the C-N cross-coupling of amines with aryl iodides by a benzyne mechanism. Alkyl, aryl and heterocyclic amines are compatible with this system affording the aminated products in high to excellent yield.
- Rout, Laxmidhar,Saha, Prasenjit,Jammi, Suribabu,Punniyamurthy, Tharmalingam
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supporting information; experimental part
p. 395 - 398
(2009/04/10)
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- A novel salt-free ruthenium-catalyzed alkylation of aryl amines
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The alkylation of aryl amines using cyclic amines such as pyrrolidine proceeds via borrowing hydrogen methodology in the presence of 1 mol % Shvo catalyst. During the reaction multiple carbon-nitrogen cleavage and formation occurred. This novel reaction sequence leads to N-aryl-pyrrolidines and -piperidines.
- Hollmann, Dirk,B?hn, Sebastian,Tillack, Annegret,Parton, Rudy,Altink, Rinke,Beller, Matthias
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p. 5742 - 5745
(2008/12/22)
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- Facile N-arylation of amines and sulfonamides and O-arylation of phenols and arenecarboxylic acids
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An efficient, transition-metal-free procedure for the N-arylation of amines, sulfonamides, and carbamates and O-arylation of phenols and carboxylic acids has been achieved by allowing these substrates to react with a variety of o-silylaryl inflates in the presence of CsF. Good to excellent yields of arylated products are obtained under very mild reaction conditions. This chemistry readily tolerates a variety of functional groups.
- Liu, Zhijian,Larock, Richard C.
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p. 3198 - 3209
(2007/10/03)
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- Studies on Pd/imidazolium salt protocols for aminations of aryl bromides and iodides using lithium hexamethyldisilazide (LHMDS)
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The reactions of a range of secondary amines with aryl bromides and iodides have been performed using an in situ protocol involving palladium and imidazolium salts. Many of these reactions proceed at room temperature, providing a mild protocol for aminations of aryl iodides and bromides. Key to the success of this procedure is the use of lithium hexamethyldisilazide (LHMDS) as base.
- Conesa Lerma, Israel,Cawley, Mark J.,Cloke, F. Geoffrey N.,Arentsen, Katherine,Scott, James S.,Pearson, Stuart E.,Hayler, John,Caddick, Stephen
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p. 5841 - 5848
(2007/10/03)
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- Amino acid promoted CuI-catalyzed C-N bond formation between aryl halides and amines or N-containing heterocycles
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CuI-catalyzed coupling reaction of electron-deficient aryl iodides with aliphatic primary amines occurs at 40 °C under the promotion of N-methylglycine. Using L-proline as the promoter, coupling reaction of aryl iodides or aryl bromides with aliphatic primary amines, aliphatic cyclic secondary amines, or electron-rich primary arylamines proceeds at 60-90 °C; an intramolecular coupling reaction between aryl chloride and primary amine moieties gives indoline at 70 °C; coupling reaction of aryl iodides with indole, pyrrole, carbazole, imidazole, or pyrazole can be carried out at 75-90 °C; and coupling reaction of electron-deficient aryl bromides with imidazole or pyrazole occurs at 60-90 °C to provide the corresponding N-aryl products in good to excellent yields. In addition, N,N-dimethylglycine promotes the coupling reaction of electron-rich aryl bromides with imidazole or pyrazole to afford the corresponding N-aryl imidazoles or pyrazoles at 110 °C. The possible action of amino acids in these coupling reactions is discussed.
- Zhang, Hui,Cai, Qian,Ma, Dawei
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p. 5164 - 5173
(2007/10/03)
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- An air and thermally stable one-component catalyst for the amination of aryl chlorides
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(Matrix presented) In this paper we report a new, highly efficient palladacyclic precatalyst that is air, moisture, and thermally stable and obviates the need to employ a glovebox. We have developed a convenient one-component precatalyst for the amination of aryl chlorides that overcomes many of the limitations of those previously described.
- Zim, Danilo,Buchwald, Stephen L.
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p. 2413 - 2415
(2007/10/03)
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- Substituted 4H-chromenes and analogs as activators of caspases and inducers of apoptosis and the use thereof
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The present invention is directed to substituted 4H-chromenes and analogs thereof, represented by the general Formula I: 1wherein R1-R5, A, Y and Z are defined herein. The present invention also relates to the discovery that compounds having Formula I are activators of caspases and inducers of apoptosis. Therefore, the activators of caspases and inducers of apoptosis of this invention can be used to induce cell death in a variety of clinical conditions in which uncontrolled growth and spread of abnormal cells occurs.
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- Nickel(0)/dihydroimidazol-2-ylidene complex catalyzed coupling of aryl chlorides and amines
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A general and simple nickel-catalyzed coupling of aryl chlorides and amines is reported. The scope and limitations of the coupling process using Ni(0), 1,3-bis(2,6-diisopropylphenyl)dihydroimidazol-2-ylidene, and NaO-t-Bu as base were investigated. Secondary cyclic and acyclic amines and anilines provided the arylamine coupling products in good to excellent yields. Compared to palladium-catalyzed aminations, this procedure offers an alternative route to N-substituted anilines starting from readily available aryl chlorides.
- Desmarets, Christophe,Schneider, Raphael,Fort, Yves
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p. 3029 - 3036
(2007/10/03)
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- Reductive one batch synthesis of N-substituted pyrrolidines from primary amines and 2,5-dimethoxytetrahydrofuran
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The construction of the pyrrolidine ring about a nitrogen of a primary amine by a reductive condensation reaction using 2,5- dimethoxytetrahydrofuran and sodium borohydride in acidic water medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electron effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups. The reaction allows the introduction of two deuterium atoms, with label conservation, in both the α-positions of the pyrrolidine ring by the use of sodium borodeuteride instead of sodium borohydride.
- Verardo, Giancarlo,Dolce, Anna,Toniutti, Nicoletta
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- Effect of Different Dialkylamino Groups on the Regioselectivity of Lithiation of O-Protected 3-(Dialkylamino)phenols
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The lithiation of 3-(dialkylamino)phenols (dialkylamino = 1-pyrrolidynyl, 1-piperidinyl, 4-morpholinyl, and dimethylamino) O-protected by a methyl, a methoxymethyl, or a carbamoyl group (X) has been studied.The results demonstrate that the site of lithiation depends on the relative ortho-directing capacities of both the dominant OX and the dialkylamino groups.With the moderate ortho-directing methoxy group the lithiation occurs exclusively (1b and 1c) or predominantly (1a) ortho to both substituents.The site of lithiation of the N,N-dialkyl-3-(methoxymethoxy)anilines 4a-c depends on the solvent used and on the type of dialkylamino group.With a strong ortho-directing group such as carbamoyloxy (9a,b,d) the lithiation takes place at the least hindered ortho position.In the absence of an electrophile the lithiated carbamates 9a,d and 10a,d rearrange stereospecifically to the corresponding benzamides 13a,d and 14a,d, respectively.
- Skowronska-Ptasinska, Maria,Verboom, Willem,Reinhoudt, David N.
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p. 2690 - 2698
(2007/10/02)
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