Cw-Jasmone

The Nef reaction can also be carried out with reducing agents. Aqueous titanium chloride reduces nitro compounds to imines, which are readily hydrolyzed to carbonyl compounds (Eq. 6.17).28 The Michael addition of nitroalkanes to enones followed by reaction with TiCl3 provides an excellent route to 1,4-diketones and hence to cyclopentenones. For example, cw-jasmone is readily obtained,28 as shown in Eq. 6.18. 

Simple reactivity inversion" implies using an umpoled synthon whose origin has, in principle, nothing in common with the synthon with "unnatural" polarity. An example of this type of reactivity inversion is found in one of the possible synthesis of cw-jasmone (3) in which the nitroethane (4) is used as an equivalent of an "acetyl anion" and reacts with an a,P-unsaturated ketone to give the corresponding 1,4-bifunctional system which can then be transformed by a Nef-type reaction into the dissonant 1,4-dicarbonyl system [5]. An intramolecular aldol condensation finally affords the target molecule (Scheme 5.3). 

The main volatile component of jasmin oil is benzyl acetate. However, minor components such as indole [120-72-9], cw-jasmone [488-10-8], and methyl jas-monate [1211-29-6] contribute strongly to the typical jasmin fragrance [544-549]. 

Assereg, J.H., Glase, S.A., and Welch, S.C. 1987. 3-Chloro-2-[(diethoxyphosphoryl)oxy]-l-propene a new reagent for a one-pot cyclopentenone annelation. Synthesis of desoxyal-lethrolone, cw-jasmone, and methylenomycin B. Journal of Organic Chemistry, 52(8) 1440-50. 

The a-sulfenyl group can be replaced by a benzothiazolthio group, as demonstrated in the synthesis of the 1,4-diketone (CXXXIV), a precursor of cw-jasmone [Eq. (65)] [10]. The geminal dicarboxylic acid (CXXXVI) can also be transformed into the 1,4-diketone (CXXXIV) by electrochemical decarboxylation as in Eq. (66) [6], suggesting that the substituted malonic acid group is synthetically equivalent to a carbonyl group. 

Thus, dihydrojasmone, " cw-jasmone, a precursor of methylenomycine B, dicran-enone A, a member of a new class of fatty acids having a cyclopentenone ring structurally similar to prostanoids and jasmonoids, have been synthesized from the 1-hydroxycyclopro-panecarbaldehyde derivatives, either via thermal C3 Cj or acid induced C3 -> C4 C5 ring expansions. ... 

Koch, T., Bandemer, K., and Boland, W. 1997. Biosynthesis of cw-jasmon A pathway for the inactivation and the disposal of the plant stress hormone jasmonic acid to the gas phase Helv. Chim. Acta 80 838-50. 

This route was used for a synthesis of cw-jasmone (8) from (5) as shown in the formulation. 

Beginning with 3-oxycyclopentane methylcarboxylate some natural products have also been synthesized. The key intermediate for the preparation of dihydro-jasmone cw-jasmone (Eq. 123) and sarkomycin (Eq. 124) is a keto-lactone, which is obtained from 3-oxo-cyclopentane methylcarboxylate (Eq. 122)... 

Shown below is the final step in a synthesis of an important perfume constituent, cw-jasmone. Which reagents would you choose to carry out this last step ... 

This methodology was also applied to the crossed Claisen reaction between carboxylic acids and methyl hexanoate. The carboxylic acids are initially converted to mixed anhydrides by reacting their in situ formed sodium carboxylates with chlorofor-mates these intermediates then react with NMI as shown previously to form electrophilic acyl ammonium species (eq 46). This strategy was applied to the synthesis of natural perfumes such as (/ )-muscone and cw-jasmone. ... 

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