Correlations of the Specific Rates of Solvolysis of Aromatic Carbamoyl Chlorides, Chloroformates, Chlorothionoformates, and Chlorodithioformates Revisited

Abstract

Additional specific rates of solvolysis are determined for phenyl chloroformate. These values are combined with literature values to give a total of 49 data points, which are used within simple and extended Grunwald-Winstein treatments. Literature values are also brought together to allow treatments in more solvents than previously for three N-aryl-Nmethylcarbamoyl chlorides, phenyl chlorothionoformate, phenyl chlorodithioformate, and N,N-diphenylcarbamoyl chloride. For the last two listed, moderately strong evidence for a meaningful inclusion of a term governed by the aromatic ring parameter (I) was indicated. No evidence was found requiring inclusion of this parameter for ionization reactions with only one aromatic ring on the nitrogen of carbamoyl chlorides or for the solvolyses of the chloroformate or chlorothionoformate proceeding by an addition-elimination (associationdissociation) mechanism.

On the Importance of the Aromatic Ring Parameter in Studies of the Solvolyses of Cinnamyl and Cinnamoyl Halides

“…Koo’s claim [24, 33] of the presence of a through conjugation of the ring π system with the reaction center in phenyl chlorothionoformate (PhOCSCl) was invalidated [34] lately as no evidence was found requiring inclusion of the h parameter for ionization reactions with only one aromatic ring on the nitrogen of carbamoyl chlorides, or for the solvolyses of the chloroformate, or chlorothionoformate proceeding by an addition-elimination (association-dissociation) mechanism.…”

“…A close examination of the data presented in Table 4 shows that for the three substrates in 24 common solvents, applications of equations 1 and 3 (without the lN T term) gave exceedingly poor correlation coefficients ( R ) and F -test values. This indicates that the correlations are very sensitive to solvent nucleophilicity, with a possibility for the further need of nucleophilic solvation [2, 17, 30, 31, 34, 37, 38] of the developing transition state.…”

“…Additionally, for a number of substrates [2, 34, 42-48], there have been several instances where removal of the TFE-EtOH points have led to a considerable improvement of the goodness-of-fit parameters in Grunwald-Winstein linear free energy plots. Also presented in Table 4 are our correlation analysis results for 3, 4 , and 5 , with the exclusion of the data points in TFE-EtOH.…”

Understanding Solvent Effects in the Solvolyses of 4-Fluorophenyl Chlorothionoformate

“…As a result a number of research groups [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] are now involved in the investigation of the hydrolysis, aminolysis and alcoholysis of alkyl and aryl chlorothionoformates. Queen [4], in an analysis of the hydrolysis of a series of alkyl chlorothionoformates together with their activation parameters and solvent isotope effects, concluded that these compounds hydrolyze by S N 1 mechanisms.…”

Solvolysis Reaction Kinetics, Rates and Mechanism for Phenyl N-Phenyl Phosphoramidochloridate

“…The solvolyses of 1-adamantyl chlorformate 18 (l/m = ~0); 2-adamantyl chlorformate 17b (l/m =~0.6); N,N-diphenyl carbamoyl chloride 19 (l/m = 0.40); and isopropyl chloride 20 (l/m = 0.54), are indicated to proceed by the ionization pathway (S N 1). In the reactions of dimethyl thiophosphorochloridate 3 (l/m = 2.1); N,N,N',N'-tetramethyl diamidophosphorochloridate 4 (l/m = 1.8); 2-phenyl-2-ketoethyl tosylate 5 (l/m = 1.8); diphenyl thiophosphinyl chloride 6 (l/m = 1.6); and 9-fluorenyl chloroformate 7 (l/m = 2.2) solvolysis, an S N 2 or an addition-elimination pathway is dominant ( Table 3).…”