Perchlorate esters. 7. Solvolysis of 2-adamantyl perchlorate: rate and product studies

Abstract

2895One reaction gave 60.0/40.0 for PrOz-do-/PrOz-dl by NMR and 60.4139.6 from microwave (MW) transitions. The second reaction gave 46.3153.7 by NMR and 46.21533 by MW. Five MW transitions2' were used; the precision of the MW and NMR ratios were similar.MW spectroscopy was employed to determine the relative amounts of EtOz-do, -d2. and -d4. The intensities of five microwave transitions (lo6,, and 1311,3 -1312.2 for EtOz-do; 139,4 -1310,3 and,l4,,,, -1411,3 for EtOz-d,; 138,5 -139,4 for EtOz-d,) were used following procedures previously worked Because of the spectral complexity and the slow decomposition of EtOz in the MW cell, the uncertainties cannot be further reduced without considerable effort.Overall yields were determined by manometric methods. In order to remove most of the acetaldehyde from the ozonides, the mixture was distilled from a -78 "C trap for -1 h. The NMR indicated that the acetaldehyde was reduced to about 5% or less. Some ozonide may also have been lost during the long distillation, but their overall yields still ranged from 70% to 85%. No systematic differences were evident between runs at low and high acetaldehyde concentrations.

Effect of the leaving group solvation on solvolytic behavior of benzhydryl derivatives

“…Low m values have usually been coupled with relatively positive DS z , as was demonstrated for 2-adamantyl perchlorate and 1-adamantyl picrate. [20][21][22] However, DS z values obtained with benzhydryl carbonates and DNBs are not considerable more positive than those for chlorides. This might be due to more restricted internal motion in the transition states than in the ground state of the benzhydryl system, which is not the case with, for example, the rigid adamantyl system.…”

“…It has been demonstrated repeatedly that the different extent of solvation of the transition state, due to dispersal of a positive charge in the electrofuge [14][15][16] or a negative charge in the LG, influences the solvolytic behavior. [17][18][19][20][21][22][23] In order to study the Scheme 1.…”

Rate and Product Studies of Solvolyses of Benzyl Fluoroformate

“…The infinity titers were fully consistent with the amounts of benzyl fluoride indicated by gas chromatography. The percentages of products formed during the solvolyses were determined by response-calibrated GLPC, as previously described [7,10,22], using a Chromatopac C-R3A column. Typical retention times (in min) were: benzyl 2,2,2-trifluoroethyl carbonate, 16.7; benzyl alcohol, 22.9; benzyl ethyl carbonate, 32.4.…”

Sixty Years of the Grunwald–Winstein Equation: Development and Recent Applications

“…For a given solvent, Y X values do not, normally, vary widely, but there are examples with quite large differences. 16,17 (b) Establishment of the N T scale A second development involved the establishment of several scales of solvent nucleophilicity. A major problem in applying Equation (3) to the determination of a scale of solvent nucleophilicity is that with Equation (4) it is impossible to determine directly the appropriate m RX value for the solvolytic displacement reaction of the standard (l = 1) substrate (RX).…”