Linalyl and Lavandulyl Esters

Among the linalyl esters, the acetate is by far the most important fragrance and flavor substance. The formate, propionate, and butyrates are used in small amounts. 

Esterification of linalool requires special reaction conditions since it tends to undergo dehydration and cyclization because it is an unsaturated tertiary alcohol. These reactions can be avoided as follows esterification with ketene in the presence of an acidic esterification catalyst below 30 °C results in formation of linalyl acetate without any byproducts [71]. Esterification can be achieved in good yield, with boiling acetic anhydride, whereby the acetic acid is distilled off as it is formed a large excess of acetic anhydride must be maintained by continuous addition of anhydride to the still vessel [34]. Highly pure linalyl acetate can be obtained by transesterification of tert-butyl acetate with linalool in the presence of sodium methylate and by continuous removal of the tert-butanol formed in the process [72]. 

Dehydrolinalool, obtained by ethynylation of 6-methyl-5-hepten-2-one, can be converted into dehydrolinalyl acetate with acetic anhydride in the presence of an acidic esterification catalyst. Partial hydrogenation of the triple bond to linalyl acetate can be carried out with, for example, palladium catalysts deactivated with lead [73]. 

Linalyl acetate is used extensively in perfumery. It is an excellent fragrance material for, among others, bergamot, lilac, lavender, linden, neroli, ylang-ylang, and phantasy notes (particularly chypre). Smaller amounts are used in other citrus products. Since linalyl acetate is fairly stable toward alkali, it can also be employed in soaps and detergents. 

One synthetic route to lavandulyl acetate starts with prenyl acetate, which dimerizes in the presence of a Friedel-Crafts catalyst, such as boron trifluoride-diacetic acid [74]. 

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