Allyl sulphenic acid

Allylic sulphenic acids are transient intermediates in the rearrangement of episulphoxides carrying a suitably located H atom /ru/i5-but-2-ene episulphoxide gives diallyl thiolsulphinate via HaC=CH CHMeSOH, the product (145) existing in equilibrium with the butenyl thio-sulphoxylate (146). 

Allyl sulphenates, rearrangement of 720-736 Allylsulphenic acids 747 Allyl sulphinates, rearrangement of 670-676 Allylsulphinyipyrazolenines, photolysis of 749... 

Sulphoxides and selenoxides undergo syn elimination under thermal conditions. A 1,4-elimination of sulphenic acid from an allyl sulphoxide leads to dienes (equation 20)50. Precursor sulphoxides are generated by oxidation of corresponding sulphides. This reaction, however, did not give good results when applied to more complicated systems51. 

Uses of Saturated Sulphides, Selenides, and Tellurldes in Synthesis.— These applications are mostly based on the C—C bond-forming reactions of sulphenyl carbanions the extensive uses of vinyl sulphides and their allyl and propargyl analogues are discussed in a later section. Some methods for C—S or C—Se bond cleavage, which are used to terminate a use in synthesis, have been discussed in an earlier section other methods, notably the conversion of the sulphide into a sulphoxide followed by pyrolytic elimination of the sulphenic acid, are covered in later sections. 

The 5>>n-elimination of sulphenic and selenenic acids from unsaturated sulphoxides and selenoxides introduces a further site of unsaturation, examples being the addition of allyl alcohols to allenic sulphoxides to give ff-(allyloxy)vinyl sulphoxides... 

---