- Practical Synthesis of Amides via Copper/ABNO-Catalyzed Aerobic Oxidative Coupling of Alcohols and Amines
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A modular Cu/ABNO catalyst system has been identified that enables efficient aerobic oxidative coupling of alcohols and amines to amides. All four permutations of benzylic/aliphatic alcohols and primary/secondary amines are viable in this reaction, enabling broad access to secondary and tertiary amides. The reactions exhibit excellent functional group compatibility and are complete within 30 min-3 h at rt. All components of the catalyst system are commercially available.
- Zultanski, Susan L.,Zhao, Jingyi,Stahl, Shannon S.
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supporting information
p. 6416 - 6419
(2016/06/09)
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- Palladium-catalyzed β-acyloxylation of simple amide via sp3 C-H activation
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β-Acyloxy amides are prepared in moderate to high yields by palladium-catalyzed acyloxylation of primary sp3 C-H bonds from simple amides without any special directing group. A catalytic system of Pd(OAc)2/CF3CO2H/ K2S2O8 is available to various amides with N-substituted by linear alkanes, cyclic alkanes, and electron-deficient benzyl compounds in this reaction. Acyloxylated products could be transformed easily to the corresponding β-hydroxy amides.
- Zhou, Lihong,Lu, Wenjun
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supporting information
p. 508 - 511
(2014/04/03)
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- Formal nucleophilic substitution of bromocyclopropanes with amides en route to conformationally constrained β-amino acid derivatives
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A chemo- and diastereoselective protocol for the formal nucleophilic substitution of 2-bromocyclopropylcarboxamides with secondary amides is described. This method allows for convergent and highly selective synthesis of trans-β-aminocyclopropane carboxylic acid derivatives.
- Prosser, Anthony R.,Banning, Joseph E.,Rubina, Marina,Rubin, Michael
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supporting information; experimental part
p. 3968 - 3971
(2010/11/02)
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- Cyclic guanidine organic catalysts: What is magic about triazabicyclodecene?
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(Chemical Equation Presented) The bicyclic guanidine 1,5,7- triazabicyclo[4.4.0]dec-5-ene (TBD) is an effective organocatalyst for the formation of amides from esters and primary amines. Mechanistic and kinetic investigations support a nucleophilic mechanism where TBD reacts reversibly with esters to generate an acyl-TBD intermediate that acylates amines to generate the amides. Comparative investigations of the analogous bicyclic guanidine 1,4,6-triazabicyclo[3.3.0]oct-4-ene (TBO) reveal it to be a much less active acylation catalyst than TBD. Theoretical and mechanistic studies imply that the higher reactivity of TBD is a consequence of both its higher basicity and nucleophilicity than TBO as well as the high reactivity of the acyl-TBD intermediate, which is sterically prevented from adopting a planar amide structure.
- Kiesewetter, Matthew K.,Scholten, Marc D.,Kirn, Nicole,Weber, Ryan L.,Hedrick, James L.,Waymouth, Robert M.
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supporting information; experimental part
p. 9490 - 9496
(2010/03/24)
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- Pd-catalyzed N-arylation of secondary acyclic amides: Catalyst development, scope, and computational study
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We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the "top ring" ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate.
- Hicks, Jacqueline D.,Hyde, Alan M.,Cuezva, Alberto Martinez,Buchwald, Stephen L.
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supporting information; experimental part
p. 16720 - 16734
(2010/04/04)
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- Deuterium exchange as an indicator of hydrogen bond donors and acceptors
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Hydrogen-deuterium exchange has been used to determine the hydrogen bonding preferences of a select group of small peptides in organic solvents. This kinetic analysis permitted comparison of hydrogen bond strengths in relation to controls and also indicated the identity of both hydrogen bond donors and hydrogen bond acceptors. Copyright
- Steffel, Lauren R.,Cashman, Timothy J.,Reutershan, Michael H.,Linton, Brian R.
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p. 12956 - 12957
(2008/09/17)
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- β-Sheet hydrogen bonding patterns in cystine peptides
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Cystine peptides have been shown to adopt conformations in organic solvents that mimic small β-sheets. Relative hydrogen bond strengths, β-strand aggregation, and the identity of individual hydrogen bond donors and acceptors have been identified through h
- Cashman, Timothy J.,Linton, Brian R.
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p. 5457 - 5460
(2008/09/18)
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- Rearrangements of trihalomethyl ketones
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Trihalomethyl ketones have been prepared and their reactivity under basic conditions was investigated in terms of competition between 1,2- vs. 1,3-elimination and nucleophilic substitution. Favorskii rearrangement was the preferred process, but in those c
- Braverman, Samuel,Cherkinsky, Marina,Kumar, E. V. K. Suresh,Gottlieb, Hugo E.
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p. 4521 - 4529
(2007/10/03)
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- Reductive O- and N-alkylations. Alternative catalytic methods to nucleophilic substitution
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Different amides have been selectively mono-N-alkylated using catalytic heterogeneous palladium and carbonyl compounds as alkylating agents. The same salt free method has been applied to the synthesis of ethers from alcohols. Reaction parameters have been studied in detail and a mechanism is proposed.
- Fache, Fabienne,Bethmont, Valerie,Jacquot, Laurent,Lemaire, Marc
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p. 231 - 238
(2007/10/03)
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- Extension of the Eschweiler-Clarke procedure to the N-alkylation of amides
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The selective N-alkylation of amides (cyclic or acyclic) under hydrogen is reported using aldehydes or ketones as alkylating agents and Pd/C/Na2SO4 as catalyst. Good isolated yields are obtained (81% to 98%).
- Fache, Fabienne,Jacquot, Laurent,Lemaire, Marc
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p. 3313 - 3314
(2007/10/02)
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- N'-ACYL-N-ALKYLCARBAMOYLOXY RADICALS: ENTRIES TO AMIDYL RADICALS BY DECARBOXYLATION AND TO α-AMIDE RADICALS BY RADICAL TRANSLOCATION
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N'-Acyl-N-hydroxypyridine-2-thione carbamates react in radical chain reactions to give the title radicals which can decarboxylate or react by intramolecular hydrogen atom transfer; the competing reaction pathways are controlled by the structure of the alkyl group and the conformation of the precursor which can be influenced by addition of a Lewis acid.
- Esker, John L.,Newcomb, Martin
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p. 5913 - 5916
(2007/10/02)
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