Vinylogous nucleophilic catalysis. Tertiary amine promoted hydrolysis of 1-alkene-1-sulfonyl chlorides

Abstract

This paper is dedicated to Professor Paul de Mayo on the occasion of his 60th birthday JAMES FREDERICK KING, JOHN HENRY HILLHOUSE, and STANISLAW SKONIECZNY. Can. J. Chem. 62, 1977Chem. 62, (1984. We present evidence that the reactions of ethenesulfonyl chloride ( I ) and trcrt~s-l -propene-l -sulfonyl chloride (3) with water in the presence of pyridine, trimethylamine, and a number of other tertiary amines proceed primarily by way of an initial + vinylogous substitution reaction to form the cationic sulFne, R.;NCHRCH=SOZ. which subsequently reacts with water either by addition (and deprotonation) to form the betaine R.;NCHRCHZSOI, or by vinylogous substitution (and deprotonation) to give the alkenesulfonate anion. CHR=CHSO, (R = H or CH3). Formation of,the latter represents the first well-supported example of vinylogous nucleophilic catalysis. These conclusions are drawn from kinetic and product composition observations, including ( ( I ) a-monodeuteration in the betaine and lack of deuteration of the ethenesulfonate (CHZ=CHSO,) from the reaction in DZO, fb) rate lowerings of up to 2000-fold for 2-(and 6-) substituted pyridines from those expected from Bronsted-type relationships shown by "unhindered" pyridine bases, (c) lack of a kinetic solvent isotope effect in the reaction of 1 with 3-cyanopyridine, (d) a lower rate of reaction of 3 vs. 1 not directly correlated with product composition, and (e) formation of similar product mixtures from either 1 or Pyr'CHZCHZSOZCI CI- (180) with aqueous pyridine. For the initial + formation of the sulfene, R3NCHZCH=SOZ, the available evidence does not distinguish between a two-step mechanism via an intermediate zwitterion and a closely related concerted reaction, but for the further reaction of the sulfene a process involving a zwitterionic intermediate common to both products is favoured. For the reaction of 1 or 3 in the absence of tertiary amines evidence is presented for a direct displacement on sulfur mechanism leading to the alkenesulfonate anion, plus a small proportion (up to 15%) of formation of the 2-hydroxy-I-alkanesulfonate anion by way of the sulfene HOCHRCH=SOZ (R = H or CH3).JAMES FREDERICK KING, JOHN HENRY HILLHOUSE et STANISLAW SKONIECZNY. Can. J . Chem. 62, 1977Chem. 62, (1984. On rapporte des donnCes qui suggkrent que la rCaction du chlorure d'6thknesulfonyle ( I ) et du chlorure de propkne-l sulfonyle-l trans (3) avec de I'eau, en prCsence de pyridine, de trimkthylamine et d'un certain nombre d'autres amines tertiaires, se produit principalement par le biais d'une rkaction initiale de substitution vinylogue conduisant i la formation du sulfkne cationique R;NCHRCH=SOZ, qui rkagit ensuite avec de I'eau soit par une addition (et une dCprotonation) pour former la bCtaYne R;NCHRCHZSO, soit par une substitution vinylogue (et une dCprotonation) pour donner I'anion alcknesulfonate, CHR=CHSO, (R = H ou CH3). La formation de ce dernier compose represente le premier exemple bien document6 d'une catalyse nuclCophile vinylogue. On tire ces conclusions en se basan...

Vinylogous nucleophilic catalysis. The tertiary amine promoted reaction of ethenesulfonyl chloride with alcohols

“…As in the case of the corresponding reaction in water (12), this observation points strongly to a common pathway for the two reactions. For the aqueous system mentioned earlier it was possible to show, from appropriate labelling experiments, that essentially all of the products were formed via the sulfene (8) with no detectable interconversion between 1 and 9a.…”

“…Instrumentation, methods, and provenance of most of the starting materials and comparison compounds have been previously described (2,12,17).…”

“…The product consisted of a mixture of (i) neopentyl ethenesulfonate (total 67%) of which 80% was the undeuterated ester (5, R = Np) and 20% the monodeuterated ester, CH2=CDS020Np ( l l ) , and (ii) the betylate (total 33%) consisting (as judged by its 'Hrnr spectrum) of about 80% C5D5N+CH2CHDS020Np (12) and 20% of the a-dideuterated ester C5D5N+CH2CD2S020Np (13). Again, most of the reaction proceeds by direct formation of the sulfene (8), which is immediately trapped by NpOD to give the undeuterated ethenesulfonate (5, R = Np) and the a-monodeuterated betylate (12). The extra deuterium in 11 and 13 may be presumed to have arisen from the a-monodeuterated pyridinio-sulfonyl chloride, C5~5N+CB2CHDS02Cl C1-.…”

“…As may be seen in Scheme 1, the reaction of ethenesulfonyl chloride (1) with an alcohol and a tertiary amine might well be imagined to proceed by way of any of three different intermediates (2,3, and 4), or even by a fourth process involving a one-step, general base-assisted direct displacement. The first two pathways correspond to the usual reactions of the alkane-and arenesulfonyl chlorides (6-lo), while the third is a variation on nucleophilic catalysis, labelled "vinylogous nucleophilic catalysis" (1 1,12). This last process was unknown at the time, but we have subsequently shown that this can be the chief route of the tertiary amine promoted hydrolysis of 1-alkenesulfonyl chlorides (1 1, 12).…”

Synthesis and thermolysis of 2-(phenylthio)ethanesulfonyl chloride. The absence of a reported "rearrangement of radicals with migration of the chlorine atom from sulfur to carbon"

“…It was therefore with considerable interest that we noted two reports of two quite different reactions which in each case might reasonably have been expected to yield 2-(phiny1thio)-ethanesulfonyl chloride ( l ) , but which describe instead only the identification of the formal desulfonylation product, 2-(phenylthio)ethyl chloride (2). In the first of these papers Kandror and Freidlina reported that reaction of benzenethiol (3) and ethenesulfonyl chloride (4) gives 2, and, to account for this product, put forward a free radical rearrangement mechanism involving migration of a chlorine atom from sulfur to carbon followed by loss of sulfur dioxide (7).…”