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1 2005

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Otrzymywanie cis-jasmonu

Pawełczyk A., Zaprutko L.

Wiadomości Chemiczne

2005

[Z] 59, 5-6

509--536

The "Jasmine chemistry" started in 1899. cis-Jasmone, a naturally occurring derivative of cyclopentenone is an important constituent of the essential oil of the jasmine flowers. It occurs in jasmine oil at the amount of 2-3%. cis-Jasmone can be obtained from fresh flowers by means of time-consuming and laborious extraction process, known as enfleurage and that is why it has been the object of number synthetic efforts. 3-Methyl-2-(2-cis-penten-l-yl)-2-cyclopenten-l -one is a chemical name of cis-jasmone. From a structural point of view it is a relatively simple compound which has been synthesized many times via many different pathways. Since pioneering works of Treff and Werner and then Hunsdiecker efforts to develop efficient syntheses of this compound have been developed to find more economical procedure. Commercial synthesis of jasmone is based on the alkylation reaction of 3-methyl-2-cyclopentene-l-one using cis-pentenyl chloride in the presence of PTC catalyst. Because of the difficulty with its manufacturing, the price is still relatively high. The present short review describes methods of cis-jasmone preparation. Very interesting and economical group of methods seems to be the group that involves furan derivatives such as furfural, 2-methylfuran, furfuryl alcohol. The major disadvantage of this route are rather vigorous hydrolytic conditions that are necessary for opening the furan ring, which sometimes leads to undesired changes in the molecule Other cyclic compounds, cyclopentadiene for example, can also be used to conduct synthesis of cis-jasmone The most common and successful method to obtain correctly 2,3-disubstituted cyclopentenone is based on the preliminary preparation of unsymmetrically substituted 1,4-diketones. These useful intermediates are subsequently cyclized under basic conditions to jasmone. Synthetic ways connecting furan derivatives and cyclization of 1,4-diketones were firstly indicated in 1942 by Hunsdiecker , who carried out a complete synthesis of jasmone from 5-methylfuralaldehyde. Syntheses of jasmone have been reported by many authors but most of those routes are either too lengthy or involve expensive chemicals. This molecule is still a popular synthetic goal and the wealth of different new methods has been published.