| 10-Carboxymethyl-trans-decal-2-one (30) has been synthesized and preliminary kinetic studies of the rate of intramolecular proton abstraction alpha to its carbonyl group by the carboxylate ion acting as general base have been made. The apparent effective concentration of the carboxylate ion in 30 is ca. 100 M.;The 1(beta)-deuterated analog of 70 was synthesized and the deuterium kinetic isotope effect was determined. An unexpectedly small value of k(,H)/k(,D) = 1.5 was observed, and the mechanistic possibilities suggested by this result are discussed.;Kinetic studies of intramolecular alpha proton abstraction by 8(beta)-(2-N-morpholinoethyl)-9(alpha)-acetoxy-10(beta)-methyldecal-2-one (70) were also performed. In order to determine an appropriate intermolecular analog for this reaction, a series of trans-fused beta acetoxy ketones was synthesized and the rates of their elimination reactions catalyzed by three morphcline bases were determined. Comparison of the rate of elimination of 70 with several of these intermolecular reactions indicates an effective concentration of the intramolecular morpholino moiety in 70 of ca. 100-200 M. However, in view of uncertainty concerning the rate determining step in this reaction, this value may be too low. This study of the various intermolecular elimination reactions also permitted an assessment of the steric effect of axial substituents on the rate of proton abstraction. |
