Mechanisms of Hydrolysis of (Trimethylsilyl)methanesulfonyl Chloride. Sulfene-Enamine Reactions in Water

Article abstract of DOI:10.1021/jo00064a037

Kinetic, product analysis, and deuteration experiments are consistent with the following mechanisms of hydrolysis of (trimethylsilyl)methanesulfonyl chloride (1) (in 0.01 M KCl at 1 deg C): (a) pH /= 10.0, attack of hydroxide anion (i) at silicon to yield sulfene (5) and (ii) at an α-hydrogen to form (trimethylsilyl)sulfene (4), in each case followed by trapping of the sulfene to give either methanesulfonate (3) or (trimethylsilyl)methanesulfonate (6) salts.Aqueous potassium fluoride catalyzes the hydrolysis of 1 with formation of the methanesulfonate 3, evidently by way of silicophilic attack of fluoride anion on 1 with formation of sulfene (5).Reaction of 1 with an enamine 7 in water (at pH 8 or 9), with or without fluoride, gives two characteristic sulfene-enamine products, (i) the four-membered cycloadduct 8 and (ii) the methylsulfonyl aldehyde 9.The same or related products are also obtained from methanesulfonyl, 2-propanesulfonyl, and phenylmethanesulfonyl chlorides and enamines in water (at pH 9).Hydrolysis of 1 is also catalyzed by aniline or triethylamine evidently giving 5.