Ehara Takeru, Tanikawa Shin, Ono Machiko, Akita Hiroyuki
School of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, Japan.
Chem Pharm Bull (Tokyo). 2007 Sep;55(9):1361-4. doi: 10.1248/cpb.55.1361.
Solvolysis reaction of methyl (4S,5S)-4-(4'-methoxyphenyl)-5-tosyloxy-2(E)-hexenoate 5 in water-saturated MeNO(2) gave the 1,2-migration product, (4S,5S)-5-hydroxy-4-(4'-methoxyphenyl)-2-(E)-hexenoate 6 (55% yield), which was converted to methyl (R)-(4'-methylphenyl)hexanoate 11 in 25% overall yield (5 steps). Treatment of (R)-11 with MeLi gave tertiary alcohol congener 12, which was subjected to dehydration to afford (R)-(-)-curcumene 1. An introduction of hydroxyl group at meta-position of the aromatic ring in (R)-11 was achieved based on consecutive treatment [1) selective iodination, 2) conversion of aryl iodide to aryl boronate, 3) conversion of aryl boronate to phenol]. Thus obtained phenol (R)-16 was treated with MeLi to give tertiary alcohol congener 17, which was subjected to dehydration to afford (R)-(-)-xanthorrizol 2.
（4S,5S）-4-（4'-甲氧基苯基）-5-对甲苯磺酰氧基-2（E）-己烯酸甲酯5在水饱和的MeNO₂中的溶剂解反应生成1,2-迁移产物（4S,5S）-5-羟基-4-（4'-甲氧基苯基）-2（E）-己烯酸酯6（产率55%），其经五步反应转化为（R）-（4'-甲基苯基）己酸甲酯11，总产率为25%。用MeLi处理（R）-11得到叔醇同系物12，将其进行脱水反应得到（R）-（-）-姜黄烯1。基于连续处理[1）选择性碘化，2）芳基碘化物转化为芳基硼酸酯，3）芳基硼酸酯转化为苯酚]，在（R）-11的芳环间位引入羟基。如此得到的苯酚（R）-16用MeLi处理得到叔醇同系物17，将其进行脱水反应得到（R）-（-）-莪术醇2。
