Use of nmr method to study the stereochemistry of dienic δ-aminocarbonyl compounds

Research paper by E. P. Prokof'ev, Zh. A. Krasnaya, V. F. Kucherov

Indexed on: 01 Oct '72Published on: 01 Oct '72Published in: Russian Chemical Bulletin


Dienic δ-amino ketoesters, δ-amino ketones, and δ-amino esters have a trans-configuration of the protons at theγ, δ-double bond and exist predominantly in the S-trans-conformation. The dienic δ-amino ketones and δ-amino esters exist as the thermodynamically stable trans-isomers at theα, β-double bond, while the dienic δ-amino ketoesters represent equilibrium mixtures of the geometric isomers at the same double bond.A rapid, on the NME time scale, rotation around theα,β-double bond under the equilibrium conditions was detected in the dienic δ-amino ketoesters. A hindering of the rotation around the C-N bond was noted in these compounds.The kinetic reaction product of the addition of diethylamine to vinylacetylenic ketones and ketoesters is the cis-isomer at theα, β,-double bond, while the trans-isomer is formed as the result of subsequent isomerization. A scheme for the mechanism of these reactions was proposed.