Linear Correlation of the Solvolysis Rates of Xanthates with the Grunwald-Winstein Y Values.

Kinetics and Mechanisms of Reactions of Thiol, Thiono, and Dithio Analogues of Carboxylic Esters with Nucleophiles

“…The slopes are 0.143 and 0.0792 for the former plots in aprotic and protic solvents, respectively. For the Grunwald−Winstein plots, the slopes are 0.31, 0.32, and 0.58 for alcohols, aqueous ethanol, and phenol−benzene mixtures, respectively . These results together with MINDO/3 calculations indicate that allylic xanthates undergo [3,3]-sigmatropic rearrangement via a polarizable transition state .…”

“…For the Grunwald−Winstein plots, the slopes are 0.31, 0.32, and 0.58 for alcohols, aqueous ethanol, and phenol−benzene mixtures, respectively . These results together with MINDO/3 calculations indicate that allylic xanthates undergo [3,3]-sigmatropic rearrangement via a polarizable transition state . The thiono−thiol rearrangement of O- alkyl S- methyl dithiocarbonates (xanthates) to S- alkyl S- methyl dithiocarbonates catalyzed by substituted pyridine N -oxides and phenols has also been studied kinetically .…”

“…47b The proportion of the latter was 35.8% in phenol, 10.3% in 80% aqueous ethanol, and 4% in ethanol. 48 Plots of log of the first-order rate constants vs Reichardt 49 E T and Grunwald-Winstein 50 Y values are linear. The slopes are 0.143 and 0.0792 for the former plots in aprotic and protic solvents, respectively.…”

“…The solvolysis of O- cinnamyl S- methyl dithiocarbonate ( 12 ) in various solvents at 60 °C afforded a mixture of S- (1-phenylallyl) and S- cinnamyl S- methyl dithiocarbonates, the former product arising from a [3,3]-sigmatropic rearrangement 47b. The proportion of the latter was 35.8% in phenol, 10.3% in 80% aqueous ethanol, and 4% in ethanol . Plots of log of the first-order rate constants vs Reichardt 49 E T and Grunwald−Winstein 50 Y values are linear.…”

“…46b On the other hand, the reaction of ROCS 2with the unsymmetrical substrate 9 is faster than that with 11, indicating that ROCS 2reacts faster with the CS group compared to CO. 46b The catalytic rearrangements of O-alkyl S-alkyl dithiocarbonates (RO-CS-SR, xanthates) to S-alkyl S-alkyl dithiocarbonates (RS-CO-SR) have been subjected to kinetic analyses. 47 The solvolysis of O-cinnamyl S-methyl dithiocarbonate (12) in various solvents at 60 °C afforded a mixture of S-(1-phenylallyl) and S-cinnamyl S-methyl dithiocarbonates, 48 the former product arising from a [3,3]-sigmatropic rearrangement. 47b The proportion of the latter was 35.8% in phenol, 10.3% in 80% aqueous ethanol, and 4% in ethanol.…”