Benzo-l,3-oxathioles

Benzo-l,3-oxathiole derivatives have been reported with remarkable pharmaceutical and biochemical activities. In 2008, Bao and co-workers described a novel and efficient copper(i)-catalyzed one-pot cascade process for the formation of 2-iminobenzo-l,3-oxathioles from readily available... 

Heterocycles of this type occur widely. The benzo[l,3]dioxole ring system is often found in natural products and their degradation products, e.g., sesamol 38 lipoic acid 39 is a naturally occurring 1,2-dithiolane derivative. The 1,3-dithiolanes 40 are commonly known as 1,3-dithioacetals and have been extensively used in carbonyl group chemistry. In the absence of cyclic conjugation, ring sulfur atoms can readily exist in higher oxidation states as, for example, in the oxathiole S, -dioxide 41. 1,3,2-Dioxathiolane A-oxides 42 (cyclic sulfites) and 1,3,2-dioxathiolane A,A-dioxides (cyclic sulfates) are useful as synthetic equivalents of epoxides. 

Further properties of the parent 1,2-oxathiolane (5) have been described and representative 2,1-benzoxathiol-3-ones (6) have been prepared. The majority of work has, however, been on 5-oxidized derivatives including 5/f-l,2-oxathiole 2-oxides (7) and 2,2-dioxides (8), and their benzo derivatives... 

The 2-alkoxy-l,3-benzo-oxathioles (455), prepared from the corresponding benzo-oxathiolium fluoroborates by the action of alcohols R OH in the presence of sodium hydrogen carbonate, behave as masked esters R C02R, which they... 

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