Sorbyl alcohol

Jasmonates are important odorant compounds. For the synthesis of new substances of this type, Giersch and Forris developed a domino Claisen/ene/retro-ene process which allows the acid-catalyzed transformation of sorbyl alcohol 4-285 and the cyclic acetals 4-286 into the cycloalkenone 4-292 with the proposed intermediates 4-287 to 4-291 (Scheme 4.61) [97]. A similar domino process had been described by Srikrishna and coworkers [98]. Acyclic acetals gave only the Claisen rearrangement products. 

Diorganylsilyl ethers of sorbyl alcohol (34) undergo a smooth intramolecular Diels-Alder reaction to give a mixture of bicyclic products 35 and 36 (equation 18)114. The endo/exo selectivity depends upon the steric influence resulting from the substituent on silicon atom. 

Sorbic alcohol Sorbinic alcohol Sorbyl alcohol... 

Winemakers wishing to stabilize juice with sorbate should also consider the potential presence and activity of LAB. In the absence of alcoholic fermentation and other countermeasures (SO2, filtration, etc.), bacterial reduction of the sorbic acid to sorbyl alcohol may occur. Upon blending... 

Some LAB are known to reduce sorbic acid to sorbyl alcohol, the precursor to geranium tone . As alcohol is not present, the end product is not produced until the juice is added to sweeten the wine at bottling. Subsequendy, geranium tone is produced in the bottled wine chemically and in the absence of viable LAB. Thus, where sorbic acid is used to stabilize stored juice against fermentative yeast activity, SO2 should also be considered to prevent growth of LAB (see section 1.43). 

The effect of surfactants (cetyltrimethylammonium bromide [CTAB], sodium dodecyl sulfate [SDS]) at their critical micellar concentration significantly influences the yield and diastereoselectivity of Diels-Alder reactions of acrylates with cyclopentadiene performed in water at room temperature. A recent contribution on the effects of micelle on the Diels-Alder reaction was reported by Engberts who observed that in the cycloadditions of N-substituted maleimides with cyclopentadiene, sorbyl alcohol, and sorbyl trimethyl ammonium bromide, a micellar catalysis seems to be active, but if one considers the micellar rate constant, the neat effect on the rate constant of the reaction is remarkably small. 

Can either of these processes be adapted to the present question Sorbyl alcohol is an allylic alcohol, and we have just seen (Section 14-3) that allylic halides readily undergo both Sn2 and S l displacement reactions. A good deal of Chapter 9 dealt with comparing and contrasting the behavior of haloalkanes with that of alcohols Protonation of the OH group of an alcohol opens the way to both substitution and elimination chemistry. We should therefore expect that allylic alcohols will be similarly reactive. We need next to consider whether the Sn2 or the SnI mechanism is more appropriate. 

The fact that the double bonds have moved in the course of the reaction is a helpful piece of information. Referring again to Section 14-3 and also 14-6, we note that the allylic cation that results from dissociation of a leaving group in the first step of an Sfjl reaction is delocalized, and nucleophiles can therefore attach at more than one site. Let us explore this line of reasoning by examining the carbocation derived from protonation and loss of water from sorbyl alcohol ... 

The values of bimolecular rate constants (kw ) for Diels-Alder reactions of cyclopentadiene, sorbyl alcohol (20), and sorbyltrimethylammonium bromide (21) with a series of TV-substituted maleimides are 20 to 40 times lower in SDS micelles than the corresponding rate constants (k ) in aqueous phase." The low micellar rate constants (k ) have been ascribed to the relatively apolar region of micelle, in which the reactions take place. The observed apparent second-order rate constants (k pp) for the reactions of 18 with 19a to 19c are significantly increased, up to a factor of 17 (for 18 + 19c /CTABr)." These observed data have been explained in terms of PP model (i.e., Equation 3.61, Chapter 3). However, the values of k /k remain constant at 0.23 and 0.45 for the reactions of 18 with 19a to 19c in SDS and CTABr micelles, respectively. Nearly 4-fold and 2-fold lower values of k compared to k in respective SDS and CTABr micelles are largely attributed to ionic micellar reaction environment." ... 

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