Deuterium isotope effects for migrating and nonmigrating groups in the solvolysis of neopentyl-type esters
..cap alpha..- and ..gamma..-deuterium rate effects on the solvolysis of (1-methylcyclohexyl)methyl, (1-methylcyclopentyl)methyl, and (1-methylcyclobutyl)methyl sulfonate esters have been measured and the solvolysis products examined by /sup 2/H NMR spectroscopy. The results indicate that the products of the solvolysis of all these sulfonate esters are predominantly (greater than or equal to 98%) rearranged. In the solvolysis of (1-methylcyclohexyl)methyl triflate, rearranged products with methyl migration slightly dominate over those with ring expansion. Normal isotope effects, 1.057 in 80E and 1.073 in 97T, are observed for the methyl-d/sub 3/ compound and an inverse effect, 0.963, is observed in 80E for the methylene-d/sub 4/ compound. However, in the solvolysis of both (1-methylcyclopentyl)methyl and (1-methylcyclobutyl)methyl sulfonates, the major products are those of ring expansion. In these examples, inverse effects are observed for the methyl-d/sub 3/-labeled species. The observed isotope effects can be separated into respective values of 0.927, 0.913 for the nonmigrating methyl-d/sub 3/ group and 1.177, 1.224 for the migrating methyl-d/sub 3/ group in the solvolysis of (1-methylcyclohexyl)methyl triflate and (1-methylcyclopentyl)methyl brosylate. This explains the relative intramolecular migratory aptitudes of CH/sub 3//CD/sub 3/ of 1.20-1.30 and the low ..gamma..-d/sub 9/ isotope effect in the solvolysis of neopentyl sulfonates previously reported and makes them consistent with a mechanism which involves neighboring carbon participation during ionization.
- Research Organization:
- Indiana Univ., Bloomington
- OSTI ID:
- 6584257
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 103:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM
ISOTOPE EFFECTS
SULFONIC ACID ESTERS
SOLVOLYSIS
BROMINATED AROMATIC HYDROCARBONS
DEUTERIUM COMPOUNDS
FLUORINATED ALIPHATIC HYDROCARBONS
NMR SPECTRA
AROMATICS
CHEMICAL REACTIONS
DECOMPOSITION
ESTERS
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
SPECTRA
STABLE ISOTOPES
400302* - Organic Chemistry- Isotope Effects- (-1987)