Allyl sulphoxides synthesis

The ethylaluminium dichloride-catalyzed reaction of p-toluenesulphinyl chloride with alkenes 136 successfully applied191 for the synthesis of allylic sulphoxides 137 (equation 74) may also be regarded formally as a reaction of sulphinyl chlorides with compounds containing active hydrogen atom. Treatment of an alkene 136 with one equivalent each of ethylaluminium dichloride and p-toluenesulphinyl chloride at room temperature gave the corresponding 137. This reaction is very general and proceeds in... 

The reaction of the phenylsulphinyl allylic lithium a-carbanion 342 with oxiranes was found by Guittet and Julia to give, after rearrangement and desulphurization, dihydroxy-dienes 343427 (equation 197). Demoute and coworkers have described the alkylation reaction of a very sophisticated 2-alkenyl sulphoxide 344 as a part of the total synthesis of a juvenile hormone 345428 (equation 198). Since the allylic sulphoxide carbanion has an ambident character, the alkylation may occur sometimes also at the y-position. This direction of alkylation is observed in the case of acyclic allylic sulphoxide anions 346, and results in the formation of the corresponding allylic sulphoxide 347 and vinylic sulphoxide 348423 (equation 199). 

TABLE 13. Synthesis of allyl sulphoxides from sulphenyl chlorides, RSCl, and allyl alcohols... 

Scheme 1, Allyl alcohol synthesis via allyl sulphoxides...

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. 

Methods previously used in the D-arabino-serles (Vol. 22, p.17-18) have been applied to the synthesis of derivatives (21) of 3-deoxy-D-lyxo-heptulosonic acid.22 Treatment of thioglycoside (22), prepared by acylation of a sulphur-stabilized C-1 carbanion as described previously for similar systems (Vol. 21, p.131-132), as indicated in Scheme 8 gave rise to the 4-acetamido-4-deoxy derivative (23) related to DAHP a [2,3]-sigmatropic rearrangement of an allyl sulphoxide is the key to the synthesis, and similar chemistry applied to (24) gave 3-deoxy-D-xylo-heptulosonic acid systems,23... 

The elimination of allylic sulphoxides to give (f jf )- ,3-dienes stereospecifically has been demonstrated by the synthesis of the pheromone of the codling moth (197) (Scheme 28), and the use of a stannyl group rather than silicon as a... 

A detailed study of the mechanism of the allyl sulphoxide-sulphenate rearrangement and its uses in synthesis has been reported. Rates of steroidal allyl sulphoxide rearrangements are influenced by chirality at sulphur, and configurational aspects established for compounds of this... 

The carbanions of 1-alkenyl sulphoxides 400 also react with carbonyl compounds to give the corresponding condensation products384 (equation 237). Solladie and Moine have used this type of reaction in their enantiospecific synthesis of the chroman ring of a-tocopherol 401. Addition of the lithio reagent 402 to the aldehyde 403 affords the allylic alcohol 404 in 75% yield as a sole diastereoisomer481 (equation 238). 

The formation of a- and 9-allylated sulphides by the Pummerer-type reaction of vinylic sulphoxides with allylmagnesium bromide has been reported by Iwata et al. Monoallylation and diallylation can take place, depending on the bulkiness of the yS-substituent, and both acyclic and cyclic vinyl sulphoxides undergo the reaction. This method offers applicability to asymmetric synthesis using sulfinyl chirality. 

Anuradha Ganesan, Sarojadevi Muthusamy, and Sundararajan Pudupadi R. Synthesis, cure kinetics, and thermal properties of the his (3-allyl-2-cyanatophenyl) sulphoxide/BMl hlends. J. Appl. Polym. Sci. 110 no. 1 (2008) 517-522. 

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. 

Butadienyl sulphoxides act as excellent Michael acceptors for nucleophilic acylating agents, particularly lithiated cyanohydrin ethers." The resulting allylic anions may be alkylated, and simple hydrolyses complete an efficient synthesis of dienones [equation (30)]. 

A full paper on the asymmetric synthesis of polyols using chiral allylic -hydroxy sulphoxides has been published (see Vol.21, p. 172). 

Acyclic Alditols.- A new approach to the synthesis of optically pure polyhydroxylated compounds by i) the stereospecific reduction of chiral -ketosulphoxides and ii) the stereospecific liydroxylation of chiral allylic /9-hydroxysulphoxides has been described. Thus the unsaturated ester (1) gave the chiral sulphoxide (2), which was sequentially reduced, hydtoxylated, and further reduced as outlined in Scheme 1 to give the L-arabinitol derivative (3) and hence penta-0-acetyl-L-arabinitol in high yield enantiomers are available by appropriate choice of the sulphoxide reagent. ... 

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