Cycloadditions of arylidene imines of α-aminoacidesters to a range of dipolarophiles show substantial rate enhancements in the presence of Bronsted and Lewis acids. For Bronsted acids the rate is related to the pKa of the acid and cycloadditions to reactive dipolarophiles occur at room temperature. For the Lewis acids studied the rate acceleration decreases in the order Zn(OAc)2 > AgOAc > LiOAc >
XY–ZH Systems as potential 1,3-dipoles. Part 8. Pyrrolidines and Δ<sup>5</sup>-pyrrolines (3,7-diazabicyclo[3.3.0]octenes) from the reaction of imines of α-amino acids and their esters with cyclic dipolarophiles. Mechanism of racemisation of α-amino acids and their esters in the presence of aldehydes
Imines of α-aminoacidesters with aromatic, heterocyclic, and aliphatic aldehydes generate azomethine ylides stereospecifically by a prototropic shift on heating in toluene. The azomethine ylides undergo cycloaddition to N-phenylmaleimide, maleic anhydride, and p-naphthoquinone via an endo-transition state to give racemic, single diastereoisomeric, cycloadducts. α-Aminoacids undergo analogous cycloadditions
X=Y-ZH systems as potential 1,3-dipoles. The stereochemistry and regiochemistry of cycloaddition reactions of imines of α-amino-acid esters.
作者:Ronald Grigg、James Kemp
DOI:10.1016/s0040-4039(00)93177-0
日期:1980.1
The stereochemistry and regiochemistry of cycloadditions of α-aminoacidesterimines is dependent both on imine structure and on the reactivity of the dipolarophile. Phenylglycine imines undergo competing dipole stereomutation and cycloaddition with some dipolarophiles.
Brönsted and Lewis acid catalysis of XY–ZH cycloadditions
作者:R. Grigg、H. Q. N. Gunaratne
DOI:10.1039/c39820000384
日期:——
Cycloadditions of arylidene imdines of methyl phenylglycinate show substantial rate enhancement in the presence of Brönsted and Lewisacids; for Brönstedacids the rate is related to the pKa of the acid, whilst for the Lewisacids studied the rate acceleration decreased in the order Zn(OAc)2 > AgOAc > LiOAc > Mg(OAc)2.
在布朗斯台德和路易斯酸的存在下,苯基甘氨酸甲酯的亚芳基亚胺的环加成反应显示出显着的速率增加。对于布朗斯台德酸,速率与该酸的p K a有关,而对于路易斯酸,所研究的速率加速以Zn(OAc)2 > AgOAc> LiOAc> Mg(OAc)2的顺序降低。
Grigg, Ronald; Kemp, James; Warnock, William J., Journal of the Chemical Society. Perkin transactions I, 1987, p. 2275 - 2284