109299-93-6Relevant academic research and scientific papers
Synthesis of α,β-unsaturated amides by olefin cross-metathesis
Choi, Tae-Lim,Chatterjee, Arnab K.,Grubbs, Robert H.
, p. 1277 - 1279 (2001)
Electronic and steric properties of the substituents on the amide nitrogen atom govern the yield and rate of the cross-metathesis between a variety of αβ-unsaturated amides and olefins with 1 as the catalyst. This influence is the result of deactivation of the catalyst by chelation of the carbonyl group to the metal. However, an increase in catalyst loading compensates for the chelation effect.
Asymmetric FeII-Catalyzed Thia-Michael Addition Reaction to α,β-Unsaturated Oxazolidin-2-one Derivatives
Lauzon, Samuel,Keipour, Hoda,Gandon, Vincent,Ollevier, Thierry
supporting information, p. 6324 - 6327 (2017/12/08)
A highly enantioselective FeII-catalyzed thia-Michael addition to α,β-unsaturated carbonyl derivatives was developed. The scope of the reaction was demonstrated with a selection of aromatic, heterocyclic and aliphatic thiols, and various Michael acceptors. The corresponding β-thioethers were obtained in good to excellent yields (up to 98%) and moderate to excellent enantioselectivities (up to 96:4 er). Unusual hepta-coordination of the metal and chelation to α,β-unsaturated oxazolidin-2-one derivatives allowed the construction of a coherent model rationalizing the enantioselective event. DFT calculations support the proposed model for observed stereoselectivities.
Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
Chen, Ming,Dong, Guangbin
supporting information, p. 7757 - 7760 (2017/06/21)
A direct catalytic method is described for the α,β-desaturation of N-protected lactams to their conjugated unsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method is demonstrated in a concise synthesis of Rolipram. In addition, linear amides also prove to be competent substrates, and the phthaloyl-protected product serves as a convenient precursor to access various conjugated carboxylic acid derivatives. Strong bases are avoided in this desaturation approach, and the key is to merge soft enolization with a Pd-catalyzed oxidation process.
An entry to a chiral dihydropyrazole scaffold: Enantioselective [3 + 2] cycloaddition of nitrile imines
Sibi, Mukund P.,Stanley, Levi M.,Jasperse, Craig P.
, p. 8276 - 8277 (2007/10/03)
We have developed a versatile strategy to access dihydropyrazoles in highly enantioenriched form. Dipolar cycloaddition of electron-deficient acceptors and in situ-generated nitrile imines proceeds with high regio- and enantioselectivity using 10 mol % chiral Lewis acid catalyst. A variety of dihydropyrazoles that incorporate functionality for further manipulation have been prepared. Copyright
Lanthanide Lewis acid-mediated enantioselective conjugate radical additions
Sibi, Mukund P.,Manyem, Shankar
, p. 2929 - 2932 (2007/10/03)
(figure presented) Lanthanide triflates along with proline-derived ligands have been found to be efficient catalysts for enantioselective conjugate addition of nucleophilic radicals to enoates. N-Acyl oxazolidinones, when used as achiral additives, gave meaningful enhancements in the ees for the product.
Rational Design of Highly Diastereoselective, Organic Base-Catalyzed, Room-Temperature Michael Addition Reactions
Soloshonok, Vadim A.,Cai, Chaozhong,Hruby, Victor J.,Van Meervelt, Luc,Yamazaki, Takashi
, p. 6688 - 6696 (2007/10/03)
Via the rational design of a single-preferred transition state, stabilized by electron donor - acceptor-type attractive interactions, structural and geometric requirements for the corresponding starting compounds have been determined. The Ni(II) complex of the Schiff base of glycine with o-[N-α-picolylamino]acetophenone, as a nucleophilic glycine equivalent, and N-(trans-enoyl)oxazolidin-2-ones, as derivatives of an α,β-unsaturated carboxylic acid, were found to be the substrates of choice featuring geometric/conformational homogeneity and high reactivity. The corresponding Michael addition reactions were found to proceed at room temperature in the presence of catalytic amounts of DBU to afford quantitatively the addition products with virtually complete diastereoselectivity. Acidic decomposition of the products followed by treatment of the reaction mixture with NH4OH gave rise to the diastereomerically pure 3-substituted pyroglutamic acids.
trans-3,4-Disubstituted pyrrolidines by 1,3-dipolar cycloaddition: Enantioselective approaches and their limitations
Karlsson, Staffan,Han, Fusen,Hoegberg, Hans-Erik,Caldirola, Patrizia
, p. 2605 - 2616 (2007/10/03)
In the presence of a chiral Lewis acid as co-catalyst, the acid- catalysed 1,3-dipolar cycloaddition reaction yielding trans-3,4-disubstituted pyrrolidines from an azomethine ylide and achiral α,β-unsaturated dipolarophiles proceeded with low enantioselectivity. Therefore a number of α,β-unsaturated dipolarophiles linked to chiral auxiliaries were examined as substrates. Camphorsultam was the best auxiliary and gave good diastereoselectivity (dr=74:26). When combining chiral Lewis acids with a dipolarophile linked to a chiral auxiliary, the enantio-selectivity could be slightly increased. As judged by 13C NMR, the small effect of the chiral Lewis acids on selectivity was probably due to breakdown of the initially formed complex with the dipolarophile caused by the dipole precursor.
Direct coupling procedure for the synthesis of N-acyl-2-oxazolidinones derived from α,β-unsaturated carboxylic acids
Knol, Joop,Feringa, Ben L.
, p. 261 - 268 (2007/10/03)
An efficient direct coupling procedure for the synthesis of N-acyl-2-oxazolidinones derived from α,β-unsaturated carboxylic acids is described in which 2-chloro-1-methylpyridinium iodide is employed as the dehydrating agent.
Asymmetric synthesis of anti-α-alkyl-β-amino carboxamides
Davies, Stephen G.,Edwards, Alison J.,Walters, Iain A. S.
, p. 175 - 183 (2007/10/02)
The alkylation reactions of enolates derived from the highly diastereoselective conjugate additions of lithium (R)-N-benzyl-N-α-methylbenzylamide (R)-1 to N,N-dimethyl crotonamide 2 and N,N-dimethyl cinnamide 3 have been investigated.The alkylations of en
