Allyl alcohol synthesis

General procedure for the reaction of an o-substituted aryl iodide with an allylic alcohol. Synthesis of biphenyls containing an oxoalkyl chain. 

In 1959, Kharasch et al.43 reported an allylic oxyacylation of olefins. In the presence of f-butyl perbenzoate and a catalytic amount of copper salt in refluxing benzene, olefin was oxidized to allyl benzoate, which could then be converted to an allyl alcohol upon hydrolysis. It is desirable to introduce asymmetric induction into this allylic oxyacylation because allylic oxyacylation holds great potential for nonracemic allyl alcohol synthesis. Furthermore, this reaction can be regarded as a good supplement to other asymmetric olefinic reactions such as epoxidation and dihydroxylation. 

AUyl transfer reactions, 73, 1 Allylic alcohols, synthesis from epoxides, 29, 3 by Wittig rearrangement, 46, 2 Allylic and benzylic carbanions, heteroatom-substituted, 27, 1 Allylic hydroperoxides, in... 

Figure 7.10 The mechanism of allyl alcohol synthesis in propylene oxidation with hydrogen peroxide, in the presence of PPFe3+0H/Al203.

Figure 7.13 The mechanism of intermediate C3H6Fe3+PP0H/Al203 transformation. Continuous arrows propylene oxide synthesis and dashed arrows allyl alcohol synthesis.

Certain chiral epoxides can be prepared from fl-hydroxyselenides (e.g., 43), typically intermediates for allylic alcohol synthesis. The novel reactivity of these substrates seems to be restricted to those cyclic compounds in which the hydroxy and the selenoxide groups can achieve an antiperiplanar disposition [95TL5079],... 

A three-stage synthesis of allylic alcohols has been devised (Scheme 32)," which consists of (i) alkylation of a sulfone-stabilized allylic carbanion (ii) peroxy acid oxidation of the allylic sulfone to give a 2,3-epoxy sulfone and (iii) reductive elimination of the 2,3-epoxy sulfone to give the allylic alcohol. The overall strategy is similar to that of the Evans-Mislow allylic alcohol synthesis based on the 2,3-sig-matropic rearrangement of allylic sulfoxides. However, there are regiochemical advantages to the sul-... 

Allylic sulfoxides are known to equilibrate with their isomeric sulfenates via a 2,3-sigmatropic shift, which has been developed into a useful allylic alcohol synthesis when the unstable sulfenate is trapped (Scheme 14). However, this rearrangement is reversible and so need not necessarily interfere with pyrolytic elimination of the sulfoxide, e.g. the long-chain hydroxydiene (69) was obtained on pyrolysis of the sulfoxide (68 equation 32). A study of substitution effects on the relative rates of rearrangement... 

However, the regioselectivity is also affected by statistical factors and if these two effects are in opposition, then the regioselectivity may not be very great, e.g. Scheme 22. However, one extremely useful aspect of the regioselectivity of selenoxide elimination is the marked preference for elimination to take place away from an electronegative atom. P-Oxygen substituents in particular are very effective at directing the elimination away from themselves, as indicated in equations (41) and (42), and this forms the basis of a very useful allylic alcohol synthesis (Section 5.3.4.2.2). ... 

Schlosser, M., Coffinet, D. a-SubstItutlon plus carbonyl olefinatlon via P-oxido phosphorus ylides (SCOOPY) reactions. Stereoselectivity of allyl alcohol synthesis via betaine ylides. Synthesis 1971, 380-381. 

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

Scheme 2. Analysis of the allyl alcohol synthesis by PhS migration...

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. 

Ohler, E.. and Zbiral. Ei.. Oxidative rearrangement of phosphorus containing tertiary allylic alcohols. Synthesis of (3-oxo-l-cycloalkenyl)phosphonates, -methylphosphonates, -methyldiphenylphosphine oxides and their epoxy derivatives. Synthesis, 357, 1991. 

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