title: Aggregation and Alkylation of the Cesium Enolate of 2-p-Biphenylylcyclohexanone(1).
abstract: The cesium enolate of 2-biphenylylcyclohexanone (CsBPCH), generated by deprotonation of 2-biphenylylcyclohexanone with diphenylmethylcesium, is shown to be a mixture of monomer and dimer in THF, with a dimerization constant of 1.9 x 10(3) M(-)(1). The ion pair acidity corresponds to pK = 19.30 +/- 0.05. Even in the presence of excess dimer, only monomeric CsBPCH is found to react with methyl tosylate (MeOTs), methyl p-bromobenzenesulfonate (MeOBs), hexyl tosylate (HexOTs), hexyl bromide (HexBr) and p-tert-butylbenzyl chloride (BBCl). The relative reactivities of these alkylating reagents toward monomeric CsBPCH are BBCl, 1.00; MeOTs, 1.21; MeOBs 6.7; HexBr, 0.10; HexOTs, 0.050. CsBPh(4) has essentially no effect on the rates.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720-1460.
authors.forename: Andrew
authors.initials: A
authors.lastname: Streitwieser
authors.forename: Daniel Zerong
authors.initials: DZ
authors.lastname: Wang
authors.forename: Manolis
authors.initials: M
authors.lastname: Stratakis