Login for students

Login for employees

Publication detail

Inverse neighboring group participation: Explanation of an unusual S?N alkyl migration of isothiuronium salts containing lactone group
Authors: Hanusek Jiří | Váňa Jiří | Sedlák Miloš | Kammel Richard | Roithová Jana | Škríba Anton | Jašík Juraj
Year: 2013
Type of publication: ostatní - přednáška nebo poster
Page from-to: nestránkováno
Titles:
Language Name Abstract Keywords
eng Inverse neighboring group participation: Explanation of an unusual S?N alkyl migration of isothiuronium salts containing lactone group At our department we are constantly dealing with transformation reactions of isothiuronium salts containing either a lactam , , or a lactone , moiety which represent versatile starting materials for synthesis of many important heterocycles including thiazoles, thiazolidines, thiazines, isoindoles etc. Many of these syntheses involve acid-base catalyzed ring transformations (rearrangements) proceeding under very mild conditions, even at physiological pH. Recently, we have studied an unexpected course of rearrangement of substituted S-(1(3H)-isobenzofuranone-3-yl)isothiuronium bromides giving either 2H-isoindol-2-carbothioamides or N,N?-dimethyl-N-(3-oxo-1,3-dihydro-2-benzofuran-1-yl)-thioureas depending on substitution at the isothiuronium moiety. A detailed experimental and DFT study of the S to N alkyl migration of substituted S-(1(3H)-isobenzofuranone-3-yl)isothiuronium bromide to N,N?-dimethyl-N-(3-oxo-1,3-dihydro-2-benzofuran-1-yl)thiourea (see Scheme) provided evidence for the existence of an unusual double displacement mechanism involving two consecutive back-side SN2 reactions where a carboxylate anion has a crucial role both as a leaving group as well as an internal nucleophile. The thiazetidine zwitterionic species which is involved in this mechanism as an intermediate was characterized by infrared multiphoton dissociation spectroscopy and was trapped with methyl iodide. It was found that the intermediate has a structure of a free ion pair. The double displacement mechanism can be considered as a new type of inverse lactone neighboring group participation. Inverse neighboring group participation; S?N migration; isothiuronium salts; lactone

Departments

Other Parts

Map

en.mapy.cz

Services

Popular Links

© 2023 University of Pardubice, Studentská 95, 532 10 Pardubice 2
Phone: +420 466 036 111, 466 036 112, 466 036 113
Webmaster, RSS
Data box ID: f5vj9hu
Accessibility Statement
CC BY-NC-ND 4.0Creative CommonsAttributionNonCommercialNoDerivatives