Rearrangement sulphenyl

Rearrangement of acetylenic sulphenates to the allenic sulphoxides 151 was discovered when the synthesis of propargylic ester of trichloromethanesulphenic acid 152 was attempted (equation 86). This reaction is of general scope and gives very good yields of allenic sulphoxides (Table 14) from structurally diverse cohols and various sulphenyl chlorides Reaction of alkynols 153 with benzenesulphenyl chloride in the presence... 

Radical addition, 312-323 carbon tetrachloride, 320 halogens, 313 hydrogen bromide, 316 sulphenyl halides, 320 vinyl polymerisation, 320 Radical anions, 218 Radical rearrangements, 335 Radicals, 20, 30,299-339 acyl, 306, 330, 335 addition to 0==C, 313-323 alkoxyl, 303... 

Of course (33b) could not react because of the lack of hydrogen at Cj. The following mechanism has been suggested (32) rearranges via (36) and(37) to the sulphenyl chloride (38), which can then... 

Reviews cover the topics alkynethiolates in synthesis " oxygen-exchange reactions of sulphoxides sulphonyldiazomethanes C—S bond cleavage acyl isothiocyanates radical reactions of sulphur compounds addition of sulphenyl halides to olefins " sulphenamidcs mercaptoethylation of amines sulphur as a chiral centre " stereochemistry of S and S " compounds " reductive cleavage of sulphides, synthetic uses of alkene- and alkyne-thiolates, and thio-Claisen rearrangements nucleophilic displacements at sulphur in disulphides aromatic... 

Molecular Orbital (M.O.) studies of reaction intermediates have been reported for the rearrangement of l-propenethiol, for the addition of sulphenyl halides to ethylene (sulphurane rather than thiiranium salt as intermediate), and for similar additions to alkynes (thiirenium ions or /ff-alkylthiovinyl cations, depending upon the substituents). Electronic effects of substituents on energy levels of orbitals of... 

Dithietans.—1,2-Dithietan (114) is the first isolated derivative in that class. It arises by dimerization of ethyl sulphine, probably by rearrangement of a first-formed sulphenyl sulphinate (see Chap. 3, Pt. II, p. 161). 

The silyl substituted dithiol (Mc3SiSCF2)2, prepared from the sulphenyl chloride CISC2F4SCI (4) and (Mc3Si)2Hg, reacts with the dichlorides RECI2 (E = P, As) to give the heterocycle, the phosphorus derivative undergoing a Michaelis-Arbuzov rearrangement, but not the arsenic one (equation 12). These heterocycles also result directly from (4) and the bis-silyl phosphine or arsine. ... 

A new synthesis of unsaturated aldehydes centres on the [2,3]rearrangement which occurs on sulphenylation of 3-trimethylsilylallyl alcohols (Scheme 24). ° ... 

Heating compounds containing the system C C—C—S—C=C in hexa-methylphosphoramide (HMPA) gives 2if-thiopyrans (247). Isomeric thio-phens appear when the reaction is conducted in the presence of amines. Allene sulphoxides (248) are readily available by reaction of alkynols with sulphenyl chlorides to form labile sulphenyl esters, which rearrange to (248). The two chiral centres in these molecules (sulphoxide and allene) result in... 

Enolates of dithioesters condense with alkyl alkanethiosulphonates to give the S-sulphenylated compounds (200), which rearrange to the a-sulphenyl dithioesters (201) on treatment with base. Esters (201) can be obtained directly from the enolates in liquid ammonia. 

Allylic thiocarbamates (145) are available from ketones by sequential condensation with vinyl-lithium species and dimethylthiocarbamoyl chloride followed by a [3,3] sigmatropic rearrangement. It has now been shown that these can be used as precursors to a,jS-unsaturated esters by bis-sulphenylation and mercury(ii)-promoted hydrolysis (Scheme 39). Only the B-isomers are produced when the final product (146) is unsubstituted i.e. = H) or carries an a-methyl... 

---