LITHIUM DIALKYLAMIDES. 13C PARAMETERS AND SLOW PROTON TRANSFER

Article abstract of DOI:10.1016/S0040-4039(00)88702-X

The changes in 13C chemical shifts for the structural change R2NH -> R2N-Li have been measured for a series of dialkylamines.These lithiation shifts are largest at the alpha carbon (3.7-9.7 ppm) and decrease in the order α > β > χ > δ.The rates of lithium-hydrogen interchange between R2NH and R'2N-Li have been determined.The activation energies are large (9 - 17 kcal/mole) and increase as the size of R or R' increases.The slow exchange permits the direct measurement of acidity differences between pairs of amines using 13C nmr.