3-Thietanones ketenes

These reactions, first described by Staudinger, have received little attention. A more recent investigation shows that the C -S bond of the thiones regioselectively adds across the C—C bond of the ketenes (equation 11) to form 2-thietanones (p-thiolactones). Primary adducts have been isolated only in a few cases. Most often they spontaneously decompose to yield an ene and COS (equation 12). 

Treatment of diethyl ketals of 3-thietanone 1,1-dioxide with bases (NaOH, phenyllithium" ) results in the elimination of ethanol to give 3-ethoxythiete 1,1-dioxides, for example, 257. 3-Methoxy-2H-thiete 1,1-dioxide is obtained by elimination of methoxytrimethylsilane from the ketal of 2-trimethylsilyl-3-thietanone 1,1-dioxide. The cycloaddition of ketene yy.,4i7,494b.495a,s93,6oo. 49sa,60i sulfenes derived from... 

Thietanone 1,1-dioxide ketals and 3-aminothiete 1,1-dioxides are readily available by cycloaddition of sulfenes to ketene acetals and enamines, respectively (Section V.3.B.). Hydrolysis of these ketals " and the aminothiete sulfones (which are enamines) " " gives 3-thietanone 1,1-dioxides in fair to good yields, as exemplified by the hydrolysis of 133 and 402. Aqueous mineral acids or acidic ion-exchange resins catalyze the reaction. Cis-2-chloro-2,4,4-trimethyl-3-morpholinothietane 1,1-dioxide reacts with N sodium hydroxide to give 38% 2,2,4-trimethyl-3-thietanone 1,1-dioxide, but the trans isomer is recovered unchanged. 3-Methoxy- and 3-ethoxythiete 1,1-dioxide (enol ethers) are also hydrolyzed to 3-thietanone 1,1-dioxide. In several cases, the hydrolysis products are written as enols of the 3-thietanone sulfone. ... 

Photolysis of 3-thietanone involves both singlet and triplet excited states the initial products are sulfene and ketene, as determined by IR spectroscopy at liquid nitrogen temperatures in a pentane matrix.When the photolysis is done in methanol, isopropyl alcohol, or r-butyl alcohol, these intermediates are trapped as the acetate and methanesulfonate esters. In diphenylmethanol solvent, the bis-diphenylmethyl ether is formed by displacement of the alcohol on the sulfonate ester. Photolysis of tetramethyl-3-thietanone 1,1-dioxide gives dimethylketene. ... 

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