Rate and Product Studies with 2-Adamantyl Fluoroformate under Solvolytic Conditions

Abstract

The specific rates of solvolysis of 2-adamantyl fluoroformate have been measured at 25.0 degrees C in 20 pure and binary solvents. These are well correlated using the extended Grunwald-Winstein equation, with incorporation of the NT solvent nucleophilicity scale and the Y-Cl solvent ionizing power scale. The sensitivities (l = 2.15 +/- 0.17 and m = 0.95 +/- 0.07) toward the changes in solvent nucleophilicity and solvent ionizing power, and the k(F)/k(Cl) values are very similar to those previously observed for solvolyses of n-octyl fluoroformate, consistent with the addition step of an addition-elimination pathway being rate-determining. For aqueous ethanol, measurement of the product ratio allowed selectivity values (S) to be determined. The results are compared with those reported earlier for 2-adamantyl chloroformate and mechanistic conclusions are drawn. Copyright (c) 2007 John Wiley & Sons, Ltd.