Kinetic and product analytical studies of the solvolysis of 2-adamantyl azoxytosylate and related compounds in a range of solvents

Abstract

Rate constants for the solvolysis of 2-adamntyl asoxytosylate were measured in, (a) acetic acid, (b)%v/v trifluoroethanol: water, (50TFE) and (c) 80%v/v trifluoroethanol:water, (80FTE); and for 2-adamntyl tosylate in (a) 50TFE, (b) 80TFE and (c) 90%v/v trifluoroethanol: water, (90TFE). The products from the solvolysis of 2-adamantyl asoxytosylate in acetic acid, ethanol, aqueous ethanol, trifluoroethanol and aqueous trifluoroethanol were analysed by a combination of capillary glc and hplc. Significant yields of 2-adamantyl tosylate are obtained from internal ion pair combination (32% in acetic acid) which decrease with the increasing ionising power of the solvent. Products from the solvolysis of bicyclo [2.2.2] octan-2-yl asoxytosylate in 97%w/w hexafluoroisopropan-2-ol: water have also been analysed. Product distributions from the asoxytosylate setic ystems are much closer to those obtained from the corresponding tosylates than those from the corresponding solvolytic deamination even though the rate-determining step in the solvolysis of the asoxytosylates resembles much more closely the deaminative fragmentations. These results allow new insights into the nature of deamination generally, and an explanation is offered as to the reason behind the formation of rearranged products in these reactions.