Allyl sulphide

Using an equimolar quantity of allyl methyl sulphide and ds-pent-2-ene resulted in incomplete reaction of the allyl sulphide and some self-metathesis of the sulphide substrate. When an excess (4 equiv) of but-2-ene was used, however, the desired but-2-enyl sulphide was formed in a good yield at ambient temperature. In this case, the large quantities of unwanted hydrocarbon starting material and self-metathesis products were gaseous alkenes and therefore easily removed. Using a large excess of one alkene to improve the yield of the desired cross-metathesis product in this way is obviously only viable if this alkene is inexpensive and both it and its self-metathesis product are easily removed. 

Unfortunately, this product was isolated as a mixture with diene 36, formed from cross-metathesis with a second equivalent of the allyl sulphide, and was contaminated with some polymeric residues. It is also important to note that an excess of the sulphide was required to suppress competing ROMP of the norbornene. A similar result was obtained for the reaction of allyl methyl sulphide with cyclop entene. 

Competing oxygen transfers from ortho nitro groups to sulphur and carbon, respectively, have been studied for allyl sulphide, styryl sulphides, allenyl sulphides and ethynyl sulphides86 - 89. 

Sulphonium ylides are in certain cases unstable and they undergo further transformation affording useful final products. In this way allylic sulphides and selenides were used to transfer an alkylthio- or alkylseleno-group onto the a-carbon of / -dicarbonyl compounds in the form of their ylides the sequence of reactions were a transylidation followed by [2,3]-sigmatropic rearrangement. 

Thio-ethers.— Ethers derived from the unsaturated hydrocarbons are known but are not important. The corresponding sulphur compounds, viz., the thio-ethers, are, however, of considerable importance and are represented by a commonly occurring substance. The thio-ether related to allyl alcohol is known as allyl thio-ether, or, also as allyl sulphide. It is made, like the thio-ethers of the saturated series, by treating the iodide of the hydrocarbon with potassium sulphide. 

Oil of Garlic.—This compound, usually known by the latter name, allyl sulphide, is a constituent of oil of garlic and is a liquid with an odor resembling that of garlic. 

Substituents X and Y based on sulphur are particularly interesting. We have already seen that vinyl sulphides are latent ketones, that allyl sulphides form useful anions and that their sulphoxides give allyl alcohols. Evans17 has used cyclic allyl sulphoxide anions in an allyl alcohol synthesis, and has used the sulphoxide 148 in a Diels-Alder synthesis88 of the hasubanan derivative 149. 

Cobalt tetraphenylporphyrin complex promotes a chain-transfer reaction in the radical polymerization of MMA to give an MMA oligomer with vinylidene unsaturation at the chain end.124 An alternative method of introducing the terminal unsaturation was disclosed by Meijs et al,125 Substituted allylic sulphides are used as chain transfer agents in which sulphide groups act as leaving group as follows ... 

Sato has reported a new route to allylic sulphides through the reaction of a-sulphenyl aldehydes (35) with phosphonium ylides or phosphonate carbanions.25 Similar reactions have been used to achieve a two-carbon... 

It is a colorless, transparent oil lighter than H O, sparingly soluble in H,0, very soluble in alcohol and ether boils at 140 (280 F.) Las an intense odor of garlic. It does not exist naturally in the plant, but is formed during the process of extraction by tbe action of H,0, probably in a manner similar to that in which essence of mustard is formed under similar circumatancea It is to the formation of allyl sulphide, which is highly volatile, that garlic owes the odor which it emits. 

DeShong (Scheme 20). Thus, reaction of nitrones with vinyl silanes followed by reduction provides Peterson - type intermediates which can then be eliminated to either Z- or E-products. Homoallylic amines were also prepared using allylsilane in the initial cycloaddition. Substitution reactions of allylic nitro compounds have received considerable attention and some examples are outlined in Scheme 21. In each case, examination of the regiochemistry of the reaction was of paramount concern, the results using palladium being superior to the SnCl mediated process. Allylic sulphides constitute yet another group of... 

A cyclopentenone annelation of an allyl sulphide has also been reported (Scheme 19). 76... 

The method last given is analogous to an important one used to prepare ethers. The sulphides are liquids, most of which have a very disagreeable odor. Allyl sulphide, (CH2 = CH.CH2)2S, is the chief constituent of the oil of garlic. 

Cmnposition.—Its active constituents are resinous matter and a volatile oil containing allyl sulphide, CgHj S. 

Characters.—Irregular masses, partly composed of tears, moist or dry. The colour of a freshly cut or broken piece is opaque white, but gradually becomes purplish-pink, and ultimately dull yellowish or pinkish-brown. Taste bitter, acrid odour (due to allyl sulphide) fetid, alliaceous, and persistent. Dissolves almost entirely in rectified spirit. Powdered with difficulty, unless triturated with carbonate of potash. 

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