Thiocyanates, allyl

Formation from Mo halides 5.8.2.12.1 Reaction with Na-Hg S.8.2.9.5 Reaction with RLi S.8.2.8.4 Reaction with ally) halides S.8.2.9.4 Reaction with allyl thiocyanates ... 

Experimental and theoretical studies on the isomerization of allyl thiocyanate to aUyl isothiocyanate have indicated that the transformation proceeds by a [3,3]-sigmatropic rearrangement involving a cychc transition state. A novel tandem [3,3]-sigmatropic rearrangement of allylic thiocyanates (129) followed by a stereo-controlled intramolecular addition of the amino function to the developing isothiocyanate group, has... 

The rearrangement of allylic thiocyanates while also a first-order process shows a much smaller dependence of rate on solvent polarity . The results of the effects of substituents, solvent and salt effects on the rate of reaction seem to indicate that the rearrangement of allylic thiocyanates essentially occurs by way of a nonionic cyclic mechanism , viz. 

Allyl thiocyanate, CH2=CHCH2SC=N, on distillation rearranges to allyl isothiocyanate, CH2=CHCH2N=C==S. Cinnamyl imd crotyl thiocyanates also rearrange the rearrangement of the former occurs without inversion, yielding cinnamyl isothiocyanate that of the latter is accompanied by inversion, yielding a-methylallyl isothiocyanate. 

Sigmatropic rearrangements have also found use in allylic S — N transposition. The rearrangement of allyl thiocyanates to allyl isothiocyanates (equation 27) ° belongs to this class as does the rearrangement of 5-allyl thioimidates (equation 28). ° ... 

The stereoselective formation of imidazolidine thiones via the rearrangement of chiral thiocyanates has recently been reported. Heating allylic thiocyanates such as 255 at 80 °C produced El-mixtures of diastereomeric isothiocyanates 256a in 92%... 

A number of allylic compounds, including allyl vinyl ethers, allyJic azides, allylic thiocyanates, and allylic sulfinates, undergo unimolecular thermal isomerization reactions. Most of these reactions are concerted, four-center processes and in most of them the allylic substituent, as well as the allylic carbon skeleton, undergoes alteration. 

Allyl thiocyanate isomerizes at similar rates in toluene, nitrobenzene, dimethylformamide, cyclohexane, and acetonitrile The reaction is slowest in the two most polar solvents, dimethylformamide and acetonitrile, and its rate is not appreciably affected by dissolved potassium thiocyanate. 

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