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

Abstract

ContentsI. Introduction 3505 II. Thioesters 3506 A. Thioalkanoates 3506 B. Thiobenzoates 3510 III. Thiocarbonates 3512 IV. Isothiocyanates 3516 V. Thioaldehydes and Thioketones 3517 VI. Thioamides and Thioureas 3517 VII. Thiocarbamates 3519 VIII. Halogenothioformates and Related Compounds 3520 IX. Conclusions 3522 X. Acknowledgments 3523 XI. References 3523 † In this review, the generic terms thioesters, thiocarbonates, thiocarbamates, and halogenothioformates will be used to comprise the corresponding thiol, thiono, and dithio derivatives.

Living Radical Polymerization by the RAFT Process

“…[13] The kinetics and mechanism of the reaction of compounds containing thiocarbonyl groups with nucleophiles has been reviewed by Castro. [197] It is well known that thiocarbonylthio groups can be transformed into thiols by reaction with nucleophiles which include pyridines, primary and secondary amines, ammonia, other thiols, and hydroxide. They may also be reduced to thiols with hydride reducing agents such as sodium borohydride, lithium aluminum hydride, or with zinc in acetic acid.…”

Mechanism of phthalate ester hydrolysis in water and in cyclodextrin mediated reactions

“…For a stepwise mechanism, a curved Brönsted plot is expected when the range of pK a of the leaving groups is wide enough. 8 We therefore considered of interest a study of the kinetic of hydrolysis of benzyl hydrogen phthalate 1 in water. Unfortunately this ester is too unreactive under conditions where the intramolecular reaction can compete with the second order rate constant for the reaction of OH -with the ester.…”

Kinetics and Mechanism of the Aminolysis of Aryl N-Allyl Thiocarbamates in Acetonitrile

“…5 Reference to Table 1 reveals that the βX values are 1.42 ~ 1.60 which are rather greater than the values normally expected for the concerted aminolysis processes, β X = 0.4 ~ 0.7 9 However, β X values smaller than 0.4 10 as well as those larger than 0.7 11 have also been observed for the concerted reactions. Especially in solvents less polar than water, larger βX (1.3 ~ 1.6) 12 are often obtained for the concerted processes. Thus the large βX values in the present work may be due to the less polar solvent used, acetonitrile.…”