173277-79-7Relevant academic research and scientific papers
Enantioselective hydrogenation of tetrasubstituted olefins of cyclic β-(acylamino)acrylates
Tang, Wenjun,Wu, Shulin,Zhang, Xumu
, p. 9570 - 9571 (2003)
Hydrogenation of a series of cyclic β-(acylamino)acrylates with tetrasubstituted olefins has been accomplished successfully with the use of Ru catalysts with chiral biaryl ligands such as C3-TunaPhos, and up to over 99% ee's have been achieved. This methodology provides an efficient catalytic method for the synthesis of both cis and trans chiral cyclic β-amino acid derivatives. Copyright
Preparation of enamides via palladium-catalyzed amidation of enol tosylates
Klapars, Artis,Campos, Kevin R.,Chen, Cheng-Yi,Volante, Ralph P.
, p. 1185 - 1188 (2007/10/03)
(Chemical Equation Presented) A Pd-catalyzed coupling of enol tosylates and amides has been developed. Ligand screening revealed dipf as the most general ligand for this transformation. A variety of enol tosylates were coupled to an array of enamides in 5
Efficient synthesis of β-amino-α,β-unsaturated carbonyl compounds
Zhao, Yuanhong,Zhao, Jingfeng,Zhou, Yongyun,Lei, Ze,Li, Liang,Zhang, Hongbin
, p. 769 - 772 (2007/10/03)
A versatile and high-yielding procedure for the synthesis of β-enamino esters and β-enaminones is presented: in the presence of tetraethyl orthosilicate, a number of highly functional β-enamino esters were obtained; this method provided an alternative for the formation of β-amino-α,β-unsaturated carbonyl compounds with mild and functional group compatible reaction conditions. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
The reaction of α-diazo-β-hydroxy esters with boron trifluoride etherate: Generation and rearrangement of destabilized vinyl cations. A detailed experimental and theoretical study
Pellicciari, Roberto,Natalini, Benedetto,Sadeghpour, Bahman M.,Marinozzi, Maura,Snyder, James P.,Williamson, Bobby L.,Kuethe, Jeffrey T.,Padwa, Albert
, p. 1 - 12 (2007/10/03)
Cyclic ethyl 2-diazo-3-hydroxy carboxylates were prepared by treating ethyl diazoacetate with LDA followed by reaction with a series of cyclic ketones. Further treatment of these α-diazo-β-hydroxy esters with boron trifluoride etherate in various solvents affords an unusual array of products. Product types and ratios were found to be strongly dependent on ring size and the solvent used. The reaction proceeds by Lewis acid complexation of the alcohol functionality of the diazo hydroxy ester with BF3 etherate followed by neighboring-group participation of the diazo moiety to generate a cycloalkylidene diazonium salt. Loss of nitrogen produces a highly reactive, destabilized, linear vinyl cation. Ring expansion via a 1,2-methylene shift leads to the formation of a more stable, bent cycloalkenyl vinyl cation. A subsequent 1,2-methylene shift results in ring contraction ultimately leading to a stable allylic cation. This cation is either trapped by the solvent or else undergoes cyclization with the adjacent ester group to give a lactone. Computational studies at the 6-31G* level were performed to determine the geometry of the optimized vinyl cations. Relative energies suggest a moderate energy gain for isomerization of the initial vinyl cation V1 to the rearranged vinyl cation V2 followed by a large stabilization in energy for subsequent conversion to the allyl cation A1. Compared with isolated product distributions, the energy profiles suggest kinetically-controlled V1 → V2 → A1 migrations. Finally, the calculations suggest that in diethyl ether the carbocations may be coordinated to a molecule of solvent resulting in "protected" cationic intermediates with nonlinear geometries.
