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|Section2= |Section3= }} Rosefuran (3-methyl-2-prenylfuran) is a liquid boiling at 103-104 °C (at 50 mm Hg), with a density of 0.9089 g/cm3 (at 30 °C), less than that of water. It is an aroma chemical which is a minor constituent of the aroma of the rose (Rosa damascene). Rosefuran is a 2,3-disubstituted furan (3-methyl-2-(3-methyl-2-buten-1-yl)furan). It has an odor threshold of 200 ppb and constitutes 0.16% of Bulgarian rose oil. Rosefuran has been established as a female sex pheromone of an acarid mite, Caloglyphus sp. Concentrations of less than 100 ng of synthetic rosefuran caused sexual excitation in males of the species. == Synthesis == Rosefuran was synthesized in 1968 by George Büchi via the organomercury compound bis(3-methyl-2-furyl)mercury. Rosefuran has been synthesized in many steps from common starting materials starting with prenyl chloride (3-methyl-but-2-en-1-yl chloride). Rosefuran has also been synthesized via cyclization of suitable acyclic precursors, such as, 5-oxogeraniol and 5-hydroxycitral (4-hydoxy-3,7-dimethyl-(E)-2,6-octadienol). Rosefuran has also been prepared via palladium catalyzed cross coupling of the methyl ester of 4-bromo-5-methyl-2-furancarboxylic acid followed by decarboxylation. Alternatively, rosefuran has been prepared from other furan derivatives. Thus, Wittig reaction of 3-methyl-2-furanacetaldehyde with triphenylphosphonium isopropylide gave rosefuran in 67% yield. The aldehyde was obtained via Claisen rearrangement of 3-(vinyloxymethyl)furan. Similarly, the readily available 3-bromofuran was reacted with 3,3-dimethylallyl bromide and lithium diisopropylamide in THF solution, followed by reaction at with methyl iodide and N-butyllithium in THF, yielding rosefuran. A patented process for the manufacture of rosefuran via condensation of 3-formylpropionic acid methyl ester with crotonaldehyde has been described. The intermediate ketoaldehyde is cyclized to a furan derivative which is converted to rosefuran in 33% overall yield via Grignard reaction to give 2-methyl-4-(3-methyl-2-furanyl)-2-butanol followed by dehydration.〔Hidetaka Tsukasa, "Manufacture of rosefuran", Jpn. Kokai Tokkyo Koho, 03151373 (1991)〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rosefuran」の詳細全文を読む スポンサード リンク
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