93845-08-0Relevant articles and documents
Why do thioureas and squaramides slow down the Ireland–Claisen rearrangement?
Kri?tofíková, Dominika,Filo, Juraj,Me?iarová, Mária,?ebesta, Radovan
supporting information, p. 2948 - 2957 (2020/01/08)
A range of chiral hydrogen-bond-donating organocatalysts was tested in the Ireland–Claisen rearrangement of silyl ketene acetals. None of these organocatalysts was able to impart any enantioselectivity on the rearrangements. Furthermore, these organocatalysts slowed down the Ireland–Claisen rearrangement in comparison to an uncatalyzed reaction. The catalyst-free reaction proceeded well in green solvents or without any solvent. DFT calculations showed that the activation barriers are higher for reactions involving hydrogen-donating organocatalysts and kinetic experiments suggest that the catalysts bind stronger to the starting silyl ketene acetals than to transition structures thus leading to inefficient rearrangement reactions.
The Regio- and Stereoselectivities of the Reaction of Allyl Acetates and Silyl Ketene Acetals Catalyzed by Pd(0) Complexes: A New Route to Cyclopropane Derivatives
Carfagna, C.,Mariani, L.,Musco, A.,Sallese, G.,Santi, R.
, p. 3924 - 3927 (2007/10/02)
Pd(0) complexes of chelating phosphines catalyzed the coupling of allyl acetates and ketene silyl acetals to yield α-allylated carboxylic acid esters.Unexpectedly alkylation of the central carbon atom (C2) of the allyl groups was also observed with concomitant formation of cyclopropane derivatives.In both cases the silyl enolate attacked the allyl group from the side opposite Pd.The yield of the reaction was sensitive to the nature of the ligand coordinated with palladium.The 1,1'-bis(diphenylphosphino)ferrocene-Pd complex was the most effective catalyst.
