Organic sulfur mechanisms. 36. Cyclopropanesulfonyl chloride: its mechanisms of hydrolysis and reactions with tertiary amines in organic media
摘要:
Cyclopropanesulfonyl chloride (1) has been synthesized and its reactions examined to see if the three-membered ring leads to unusual reactions in either 1 or the corresponding sulfene, cyclopropanethione S,S-dioxide (2). pH-rate profiles, primary kinetic isotope effects (KIE's), and pH-product ratio experiments are in full agreement with mechanisms of hydrolysis of 1 like those of a simple alkanesulfonyl chlorides (J. Am. Chem. Soc. 1992,114,1743-1749), specifically, (a) below pH 7.2 by S(N)2-S reaction with water and (b) above pH 7.3, elimination by hydroxide to form the sulfene (2) which is trapped by (i) water below pH 12.0 and (ii) hydroxide above pH 12.0. The products of the reaction of cyclopropanesulfonyl-1-d chloride (9) with triethylamine and 2-propanol in dichloromethane indicate that most of the reaction goes via 2; the analogous reaction with trimethylamine apparently proceeds by a direct formation of the sulfonylammonium chloride (14) which then yields the alpha-deuterated N,N-dimethyl sulfonamide (12, R = Me). The evident sulfene formation processes in the reaction of triethylamine with ethanesulfonyl, 2-propanesulfonyl, and cyclopropanesulfonyl chlorides show very low primary KIE's (<1.5), pointing to highly product-like transition states. Reaction of 1 with an enamine (1-pyrrolidino-2-methylpropene, 20) in the presence of a base in either water or dichloromethane gave cyclopropanesulfonpyrrolidide (23) and an aldehyde adduct (24), but no four-membered cycloadduct (21).
A catalyst‐free, charge‐transfer complex promoted coupling of sulfonyl chlorides with vicinal tertiary diamines to generate sulfonamides is presented. Mechanistic studies showed that these reactions are proceeded via charge transfer of vicinal tertiary diamines to sulfonyl chlorides, forming the unstable sulfonyl quaternary ammonium like complexes which induced the regiospecific intramolecular C−N
Sulfonamides have been prepared in high yields by the reactions of N-silylamines with sulfonyl chlorides and fluorides. In a competition experiment, the sulfonyl chlorides were found to be far more reactive than sulfonyl fluorides. The chemistry may be used to prepare aliphatic, aromatic, tertiary, secondary, and primary sulfonamides. It may also be done in the absence of solvent and the byproduct trimethylsilyl chloride recovered in good yield. Primary sulfonamides were synthesized from the sulfonyl chloride with aminotriphenyl silane (Ph3SiNH2), a conversion demonstrated with the synthesis of the carbonic anhydrase inhibitor, acetazolamide. (C) 2013 Elsevier Ltd. All rights reserved.