A detailed molecular mechanism has recently been described for the phase transfer catalyzed enantioselective alkylation of an enolate with use of the chiral quaternary cinchonidinium salt 1a. 1,2 This reaction was illustrated by a variety of examples in which a series of (S)-R-amino acid derivatives (both natural and unnatural) was prepared with enantioselectivities in the range 400:1 to 60:1 by alkylation of the tert-butyl glycinate-benzophenone Schiff base. 3 In the mechanistic model contact ion pairing takes place selectively between the anionic oxygen of the enolate and just one of the tetrahedral faces of the cationic nitrogen of 1a (for steric reasons). In addition, considerable van der Waals attraction occurs between the enolate and a complementary binding site on the quaternary ammonium cation within the contact ion pair. The combination of electrostatic and van der Waals binding results in a highly structured contact ion pair in which only one face of the nucleophilic R carbon of the enolate is accessible to the electrophilic alkylating species. 1 This mechanistic picture provides a logical explanation for the absolute stereochemical course of the catalytic alkylation process and also the very high levels of enantioselectivity which are observed. In this paper we demonstrate that this remarkably enantioselective alkylation catalyst can be applied to other enolates and that the enantioselectivity varies in a predictable way with the electronic effect of remote substituents on the enolate. In addition, we present an analysis of the alkylation process that underscores the importance of charge density and entropy in determining the level of enantioselectivity.The β,γ-unsaturated ester 2 was prepared from 4,4′-bis-(dimethylamino)benzophenone (Michler's ketone) by the following sequence: (1) reaction with γ-lithiated tert-butyl propiolate (from n-BuLi on the propiolate ester in THF at -78 °C) in THF at -15 °C for 20 h (68%); (2) catalytic reduction with 1 atm of H 2 over 5% Pd-BaSO 4 at 23 °C for 20 min (91%); and (3) dehydration with CH 3 SO 2 Cl-Et 3 N-4-N,N-(dimethylamino)pyridine in CH 2 Cl 2 at 0 °C for 30 min (86%). Reaction of 2 in 1:1 CH 2 Cl 2 -Et 2 O solution containing 10 mol % of chiral ammonium bromide 1b with various alkyl bromides or iodides