Kimachi Tetsutaro, Torii Eri, Kobayashi Yusuke, Doe Misae, Ju-ichi Motoharu
School of Pharmaceutical Sciences, Mukogawa Women's University, 11–68 Koshien Kyubancho, Nishinomiya, Hyogo, Japan.
Chem Pharm Bull (Tokyo). 2011;59(6):753-6. doi: 10.1248/cpb.59.753.
Synthesis of dehydoriso-β-lapachone (1) in both racemic and enantioenriched forms is achieved starting from reduced naphthoquinone equivalents. As for the synthesis of enantioenriched dehydroiso-β-lapachone, introduction of the asymmetric center was carried out by catalytic asymmetric epoxidation of the unfunctionalized trisubstituted olefin using Shi epoxidation diketal catalyst. The construction of isopropenylfurano-1,2-(β)-naphthoquinone was carried out by acidic ring-opening reaction of the epoxynaphthalene and the following diammonium cerium(IV) nitrate (CAN) oxidation. The absolute configuration of naturally occurring (-)-dehydroiso-β-lapachone was finally determined as (R) by comparing the measured optical rotation value of the synthetic (R)-dehydroiso-β-lapachone.
从还原萘醌类似物出发，实现了外消旋和对映体富集形式的脱氢异-β-拉帕醌（1）的合成。至于对映体富集的脱氢异-β-拉帕醌的合成，通过使用Shi环氧化二缩酮催化剂对对未官能化的三取代烯烃进行催化不对称环氧化来引入不对称中心。异丙烯基呋喃并-1,2-(β)-萘醌的构建是通过环氧萘的酸催化开环反应以及随后的硝酸铈（IV）铵（CAN）氧化来进行的。通过比较合成的（R）-脱氢异-β-拉帕醌的实测旋光值，最终确定天然存在的（-）-脱氢异-β-拉帕醌的绝对构型为（R）。
