Mary A. Doran

Addition of organolithium reagents to 1,1-diphenyl-ethylene in diethyl ether, kinetics and structure reactivity behaviors

Abstract Kinetic studies of the addition of benzyllithium, allyllithium, phenyllithium, methyllithium and n-butyllithium to 1,1-diphenylethylene in diethyl ether solution show the reactions are first order in DPE and variable order in organolithium reagent. A consequence of the differences in effective reaction orders is that the relative reactivity of these reagents is concentration dependent. Vinyllithium does not give the normal 1 1 adduct with DPE in Et2O. In the concentration range investigated, i.e. between 10−3 and 1 M organolithium, methyllithium is the least reactive and n-butyllithium is the most reactive, by a factor of ∼ 1 4000 . The effective organolithium reaction orders and relative reactivity order in Et2O are similar to those reported in tetrahydrofuran. The rate increase between Et2O and THF reaction media is smallest for phenyllithium (i.e., 90) and largest for benzyllithium, (i.e., 1700).

Kinetic study of addition of p-t-amylbenzyllithium to 1,1,-diphenylethylene in toluene

p-t-Amylbenzyllithium (I) is found to be appreciably soluble in toluene, in contrast to the very limited solubility of benzyllithium in this solvent. The reaction order in organolithium, for addition of I to 1,1-diphenylethylene, is 0.5. This kinetic behavior and reaction rate are compared to the behavior of benzyllithium in ether solutions and to the behavior of other organolithium reagents in hydrocarbon solution.