作者:Takahiro Miyake、Keisuke Uda、Masako Kinoshita、Mikio Fujii、Hiroyuki Akita
DOI:10.1248/cpb.56.398
日期:——
Total syntheses of (+)-coronarin A (1), (+)-coronarin E (2), (+)-austrochaparol (3) and (+)-pacovatinin A (4) were achieved from the synthetic (+)-albicanyl acetate (6). Dess–Martin oxidation of (+)-albicanol (5) derived from the chemoenzymatic product (6) gave an aldehyde (7), which was subjected to Julia one-pot olefination using β-furylmethyl-heteroaromatic sulfones (8 or 9 ) gave (+)-trans coronarin E (2) and (+)-cis coronarin E (12) with high cis-selectivity. The synthesis of (+)-coronarin A (1) from (+)-trans coronarin E (2) was achiev-ed, while (+)-cis coronarin E (12) was converted to the natural products (+)-(5S,9S,10S)-15,16-epoxy-8(17),13(16),14-labdatriene (13) and (+)-austrochaparol (3). By the asymmetric synthesis of (+)-3, the absolute structure of (+)-3 was determined to be 5S, 7R, 9R, 10S configurations. Homologation of (+)-albicanol (5) followed by allylic oxidation gave (7α)-hydroxy nitrile (17), which was finally converted to the natural (+)-pacovatinin A (4) in 8 steps from (+)-albicanol (5).
从合成产物(+)-albicanyl acetate (6)中获得了(+)-coronarin A (1)、(+)-coronarin E (2)、(+)-austrochaparol (3)和(+)-pacovatinin A (4)的完全合成。(+)-albicanol (5)的Dess-Martin氧化反应来自化学酶产物(6),生成醛(7),后者与β-呋喃甲基杂芳砜(8或9)进行Julia一锅法烯化反应,得到具有高顺式选择性的(+)-反式coronarin E (2)和(+)-顺式coronarin E (12)。从(+)-反式coronarin E (2)中获得了(+)-coronarin A (1)的合成,而(+)-顺式coronarin E (12)则转化为天然产物(+)-(5S,9S,10S)-15,16-epoxy-8(17),13(16),14-labdatriene (13)和(+)-austrochaparol (3)。通过(+)-3的不对称合成,确定(+)-3的绝对结构为5S,7R,9R,10S构型。(+)-albicanol (5)的同分异构化反应后,发生烯丙基氧化反应,生成(7α)-