L'azote n'est pas le site basique des amides encombrés

1993 ◽  
Vol 71 (2) ◽  
pp. 254-257 ◽  
Author(s):  
Christian Laurence ◽  
Maryvonne Helbert ◽  
Abdeljalil Lachkar
Keyword(s):  
Hydrogen Bond ◽  
Oxygen Atom ◽  
Carbonyl Group ◽  
Complexation Constants ◽  
Carbonyl Band ◽  
Iodine Complexes ◽  
Hydrogen Bond Donors

The shift of the carbonyl band of the iodine complexes with the hindered amides i-PrCON(C6H11)2, t-BuCON(C6H11)2, and t-BuCON(i-Pr2) shows that the iodine interacts with the oxygen atom of the carbonyl group. Hydrogen bond donors, such as p-FC6H4OH, CHCl3, or CHBr3, also interact with the oxygen atom of the carbonyl group. The only differences between these hindered amides and unhindered amides like MeCONMe2 are the lower complexation constants (15 L mol−1 for MeCONMe2–I2 vs. 3 L mol−1 for t-BuCON(i-Pr2) and a lower stoichiometry of complexation (for example, a mixture of 1:1 and 1:2 complexes is obtained with t-BuCON(C6H11)2 while MeCONMe2 forms mainly 1:2 complexes).

Gold setting the “gold standard” among transition metals as a hydrogen bond acceptor – a theoretical investigation

2017 ◽  
Vol 46 (15) ◽  
pp. 4960-4967 ◽  
Author(s):  
Ferdinand Groenewald ◽  
Helgard G. Raubenheimer ◽  
Jan Dillen ◽  
Catharine Esterhuysen
Keyword(s):  
Hydrogen Bond ◽  
Transition Metals ◽  
Theoretical Investigation ◽  
Gold Standard ◽  
Hydrogen Bond Acceptor ◽  
Hydrogen Bond Donors

MP2/aug-cc-pVTZ-pp calculations show that the Au(i) atom of dimethylaurate behaves as a hydrogen-bond acceptor to a range of hydrogen-bond donors.

scholarly journals Anion-Abstraction Catalysis: The Cooperative Mechanism of α-Chloroether Activation by Dual Hydrogen-Bond Donors

ACS Catalysis ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 4616-4620 ◽  
Author(s):  
David D. Ford ◽  
Dan Lehnherr ◽  
C. Rose Kennedy ◽  
Eric N. Jacobsen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bond Donors

scholarly journals New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

2016 ◽  
Vol 12 ◽  
pp. 2834-2848 ◽  
Author(s):  
Pavel Nagorny ◽  
Zhankui Sun
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Recent Progress ◽  
Halogen Bonds ◽  
Hydrogen Bond Donor ◽  
New Approaches ◽  
Substrate Activation ◽  
Non Covalent Interactions ◽  
Covalent Interactions ◽  
Hydrogen Bond Donors

Hydrogen bond donor catalysis represents a rapidly growing subfield of organocatalysis. While traditional hydrogen bond donors containing N–H and O–H moieties have been effectively used for electrophile activation, activation based on other types of non-covalent interactions is less common. This mini review highlights recent progress in developing and exploring new organic catalysts for electrophile activation through the formation of C–H hydrogen bonds and C–X halogen bonds.

ChemInform Abstract: Homoallylic Alcohols and Trichloroacetamides as Hydrogen Bond Donors for Directed Dihydroxylation.

ChemInform ◽  
2010 ◽  
Vol 33 (9) ◽  
pp. no-no
Author(s):  
Timothy J. Donohoe ◽  
Lee Mitchell ◽  
Michael J. Waring ◽  
Madeleine Helliwell ◽  
Andrew Bell ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Homoallylic Alcohols ◽  
Hydrogen Bond Donors

On the regioselectivity of the condensation of stabilized phosphoylids with 3-substituted phthalic anhydrides

1989 ◽  
Vol 67 (4) ◽  
pp. 569-573 ◽  
Author(s):  
Livain Breau ◽  
Margaret M. Kayser
Keyword(s):  
Oxygen Atom ◽  
Transition State ◽  
Carbonyl Group ◽  
Lewis Base ◽  
Carbonyl Function ◽  
Deficient Phosphorus ◽  
Phthalic Anhydrides

Condensations of stabilized phosphorane 1 with 3-substituted phthalic anhydrides were investigated. The importance of various effects influencing regio- and stereoselectivity of these reactions is discussed. It is proposed that the oxygen atom on the substituents in position 3 can act as a Lewis base toward the electron-deficient phosphorus of the ylid. The resulting complexation stabilizes the transition state for the reaction at the ortho carbonyl group, thus offsetting the usual steric and "push" effects, which favour attack at the meta carbonyl function. Keywords: Wittig condensations, phthalic anhydrides, regioselectivity, stereoselectivity.

scholarly journals Reactions and interactions between peri-groups in 1-dimethylamino-naphthalene salts: an example of a “through space” amide

2016 ◽  
Vol 88 (4) ◽  
pp. 317-331
Author(s):  
Amélie Wannebroucq ◽  
Andrew P. Jarmyn ◽  
Mateusz B. Pitak ◽  
Simon J. Coles ◽  
John D. Wallis
Keyword(s):  
Hydrogen Bond ◽  
Methyl Ester ◽  
Carbonyl Group ◽  
Dimethylamino Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Electron Donation ◽  
Protonated Cation

Abstract8-Dimethylaminonaphthalene-1-carbaldehyde reacts readily at 0°C with benzoyl or pivaloyl chloride by O-acylation and formation of a N–C bond (1.566(2)–1.568(3) Å) between the peri-substituents to give a salt. The reaction is promoted by electron donation from the dimethylamino group to the carbonyl group, akin to the properties of an amide. In contrast, the corresponding methyl ester and N,N-diisopropylamide react with acid in ether by protonation of the dimethylamino group and formation of a hydrogen bond to the carbonyl group, while under similar conditions the N,N-dimethylamide undergoes ready hydrolysis to the acid. The structures of products are determined by X-ray crystallography, and from the latter hydrolysis crystals containing zwitterionic 1-dimethylammonium-naphthalene-8-carboxylate and the corresponding O-protonated cation along with dimethylammonium and triflate ions were obtained.

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