Lilac alcohol, reactions

A ketol ether (410) which, so far as the Reporter knows, is a new natural product, has been isolated from Perilla frutescens var. acuta. All four of the lilac alcohol (411) isomers are present in the oil from flowers of lilac, a complete analysis of which has been published. Further work on the irradiation of -carotene [yielding loliolide (412), Vol. l,p. 50] has revealed the presence of further products the same reaction with zeaxanthin (413) yields the same substances, with, in addition, 3-hydroxy-/ -cyclocitral (414). ... 

All of these disconnections relied on the reaction of a carbon electrophile with a nucleophilic functional group. The alternative, reaction of a carbon nucleophile (such as a Grignard reagent) with an electrophilic functional group, allows us to do C-C disconnections on alcohols, For example, this compound, which has a fragrance reminiscent of lilac, is a useful perfume for use in soap because (unlike many other perfumes that are aldehydes or ketones) it is stable to alkali. 

C10H14O, Mr 150.22, mp 24 °C, bpm3 kPa 214-216 °C, df 0.9840, ng° 1.5170, has not yet been found in nature. The alcohol has a floral-herbaceous odor, reminiscent of lilac, and is prepared by a Grignard reaction of benzylmagnesium chloride and acetone. It is used in perfumery for various flower notes (e.g., lilac, hyacinth, mimosa). The alcohol is stable to alkali and is thus suited for soap perfumes. It is used to prepare a number of esters, which are also used as fragrance substances. 

X-Terpineol can be considered as a hydrate of limonene. Indeed, it is available by Markovnikov addition of trifluoroacetic acid to the latter, followed by hydrolysis [141]. The alcohol has a pleasant odor similar to lilac and is a constituent of cajuput, pine, and petitgrain oil. For technical applications, it is produced from a-pinene by acid-catalyzed isomerization/hydration [142]. Hydroformylation of a-terpineol has been conducted with an unmodified Rh catalyst at 69bar (Scheme 6.45) [132]. Under the conditions applied, besides the expected cyclic carbaldehydes also a linear aldehyde with a tertiary alcoholic group were obtained. The reaction product was distilled, and the main fraction collected showed a woody and nutty aroma with minty and floral topnotes. 

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