α-Effect Menschutkin alkylations

Article abstract of DOI:10.1021/jo00079a038

The Menschutkin-type alkylation of substituted N-methylanilines with methyl arenesulfonates is compared to the same reaction with substituted N- phenylhydroxylamines. The α-effects are small but measurable. The Hammett ρ parameters are not useful in this reaction series as an index of transition- state character. The use of β(1g)(Me) parameters along with β(nuc) values allows the transition states to be placed on the energy surface. The pattern is that the α-nucleophiles form tighter transition states than the normal nucleophiles. The size of the α-effect is related to the ionization potentials (IPs) computed by the AM1 Hamiltonian for a wide variety of reactions showing the α-effect. The larger α-effects depend more greatly on the IP.