title: Correlation of the rates of solvolysis of neopentyl chloroformate-a recommended protecting agent.
abstract: The specific rates of solvolysis of neopentyl chloroformate (1) have been determined in 21 pure and binary solvents at 45.0 °C. In most solvents the values are essentially identical to those for ethyl and n-propyl chloroformates. However, in aqueous-1,1,1,3,3,3-hexafluoro-2-propanol mixtures (HFIP) rich in fluoroalcohol, 1 solvolyses appreciably faster than the other two substrates. Linear free energy relationship (LFER) comparison of the specific rates of solvolysis of 1 with those for phenyl chloroformate and those for n-propyl chloroformate are helpful in the mechanistic considerations, as is also the treatment in terms of the Extended Grunwald-Winstein equation. It is proposed that the faster reaction for 1 in HFIP rich solvents is due to the influence of a 1,2-methyl shift, leading to a tertiary alkyl cation, outweighing the only weak nucleophilic solvation of the cation possible in these low nucleophilicity solvents.
authors.affiliation: Department of Chemistry, Wesley College, 120 N. State Street, Dover, DE 19901, USA.
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: D'Souza
authors.forename: Shannon E
authors.initials: SE
authors.lastname: Carter
authors.forename: Dennis N
authors.initials: DN
authors.lastname: Kevill
mesh_terms: D005466:Fluorocarbons / Q000737:chemistry*; D005561:Formates / Q000138:chemical synthesis / Q000737:chemistry*; D007700:Kinetics
chemical_list: D005466:Fluorocarbons; D005561:Formates