Rate constants of solvolysis of a-tert-butyl(2-naphthyl)methyl chloride (1), 9-fluorenyl chloride (2) and a series of monosubstituted benzhydryl chlorides (3) in a wide range of solvents were measured. Grunwald-Winsteintype correlation analysis of log k for 2 and 3 against Y BnCl , with or without nucleophilicity N, yielded less satisfactory linear correlations than that against log k(1). A new scale of solvent ionizing power, Y xBnCl , for the correlation of solvolytic reactivities of benzylic chlorides with extended charge delocalization based on log k(1) was developed. Application to the mechanistic study suggested the solvolysis of 2 and 4-nitrobenzhydryl chloride were non-limiting. Hammett plots against ' constants exhibited more negative r values in less nucleophilic solvents. In a benzhydryl chloride containing a strong deactivating substituent, such as 4-nitro, the positive charge delocalizes mainly over the unsubstituted ring in the cationic transition state. The uneven charge distribution was also confirmed by Mulliken population analysis at the level of the RHF/6-31G * //RHF/3-21G

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The solvolysis of a-tert-butyl-2-naphthylmethyl, 9-fluorenyl, and some 1-aryl-1-tert-butylmethyl tosylates (8-10) in a variety of solvents were studied. Both the single-parameter Hammett-Brown equation and the dual-parameter Yukawa-Tsuno equation showed linear correlations. The variation of r values was discussed. A new Y xBnOTs scale was developed, and the Y BnOTs scale was expanded. Solvent effects for a number of tosylates were examined. Excellent linear relationships observed from the single-parameter Grunwald-Winstein equation (Eqn. 2) for 9-fluorenyl tosylate (10) led to the conclusion that the 9-fluorenyl cation in the solvolysis transition state was unlikely antiaromatic. Anchimeric assistance in the solvolysis of 16-19 was discussed.