1was dissolved in 50 mL of ether and cooled to 0 "C. A stream of ammonia gas was passed through the solution for 10 min, the solids were filtered, and the filtrate was washed with 50 mL of 10% aqueous HCl, 80 mL of saturated ammonium chloride, and 2 X 50 mL of water. T h e solution was dried (MgS04) and the solvents were removed under reduced pressure. Distillation of the oily residue gave 7.8 g (30.1 mmol, 57%) of 4b: b p 178-180 "C (20 mm/Hg) [lit.l8 bp 130-133 "C (1 mmHg)]; 'H NMR (CDCl,) 6 0.20-0.80 (m, 4 H), 0.80-1.45 (m, 1 H), 1.50 (d, 3 H, J = 6.0 Hz), 4.15-4.80 (m, 1 H), and 7.15 ( s , 3 H); IR (neat, film) 930, 850, 800, and 780 cm-'.A total of 2.60 g (10.0 mmol) of 4b in 10 mL of piperidine was heated for 25 h in a sealed tube a t 130 "C. On cooling, some piperidine hydrobromide was filtered, and the filtrate was dissolved in 30 mL of 10% HCl solution and washed with ether. The aqueous phase was basified with NaOH and extracted with 3 X 100 mL of ether. T h e ether extracts were dried (NaZSO4) and filtered, and the solvents were removed under reduced pressure.Solvolytic rate constants are reported for reactions of 1-adamantyl picrate, 2-adamantyl trifluoromethanesulfonate (triflate), and 2-adamantyl perchlorate in binary aqueous mixtures of ethanol, methanol, acetone, trifluoroethanol, and hexafluoroisopropyl alcohol. Logarithms of solvolysis rates for various compositions of a binary mixture (aqueous ethanol, methanol, or acetone) are correlated with the solvent ionizing power (e.g., logarithms of solvolysis rates for 2-adamantyl tosylate). Variations in slopes of the correlations for picrates are attributed primarily t o electrostatic effects-more extensive delocalization of negative charge in the anionic leaving group reduces the sensitivities of the solvolyses to changes in solvent ionizing power. T h e discussion includes previous work on chlorides, bromides, and iodides. Deviations from the correlation lines for aqueous alcohol mixtures provide a measure of electrophilic assistance in acidic and fluorinated solvents. Triflates may be the only exceptions to the general pattern that electrophilic assistance by carboxylic acid solvents depends on the electronegativity of the atom(s) of the leaving group on which charge develops. Only triflates show similar deviations for fluorinated alcohol solvents. Perchlorates and picrates show enhanced reactivities in high percentage acetone/water mixtures, but it is suggested from a plot of YI vs. Ypic that lipophilic effects may not cause these deviations. (4) (a) Kevill, D. N.; Kolwyck, K. C.; Weitl, F. L. J . Am. Chem. SOC. 1970,92,7300. (b) Kevill, D. N.; Kolwyck, K. C.; Shold, D. M.; Kim, C.
