INERT-MOLECULE-SEPARATED ION-PAIRS - STEREOCHEMICAL, O-18, AND PRODUCT STUDIES

Nitrogen- and nitrous oxide-separated carbocation-carboxylate ion pairs have been prepared by five different reactions: the rearrangement of N-nitroso amides, the reaction of acid chlorides with anti-diazoates, the reaction of acid chlorides with syn-diazoates, the reaction of acid chlorides with anions of N-nitroamines, and the decomposition of N-nitroso-O-acyl-hydroxylamines. Comparative stereochemical, O-18 scrambling, and product analyses have been made where common alkyl groups (1-phenylethyl), acyl groups (2-naphthoyl), solvent, and temperature are employed. The five reactions yield the same organic products, and they proceed with the same degree of retention of configuration; the reactions that were examined show the same extent of O-18 scrambling. Interestingly, differences in product ratios were detected in a comparison of the nitroso amide and nitrosohydroxylamine reactions, with the latter reaction providing the larger proportion of ester. The results indicate that the structural differences built into the precursor molecules are averaged out with respect to two of the product characteristics, but not to all three. These reactions are proposed to proceed via nitrogen- or nitrous oxide-separated ion pairs. The reactions are little influenced by variables such as temperature and solvent, and the carbocations prepared in this manner exhibit a remarkably high reactivity. The relevance of these results to other methods of deamination is examined.