Synthesis, Absolute Configuration, and Enantiomeric Enrichment of a Cruciferous Oxindole Phytoalexin, (<i>S</i>)-(−)-Spirobrassinin, and Its Oxazoline Analog
作者:Mojmír Suchý、Peter Kutschy、Kenji Monde、Hitoshi Goto、Nobuyuki Harada、Mitsuo Takasugi、Milan Dzurilla、Eva Balentová
DOI:10.1021/jo0155052
日期:2001.6.1
spirooxazoline [(+/-)-11]. Enantioresolution of (+/-)-4 and (+/-)-11 was achieved by derivatization with (S)-(-)-1-phenylethyl isocyanate (12), chromatographic separation of diastereomeric amides 13, 14 or 15, 16, and their cleavage with CH(3)ONa. Absolute configuration of the stereogenic center in natural (S)-(-)-4 was derived from the exciton, calculated via CD methods, and unequivocally confirmed
进行了十字花科的羟吲哚植物抗毒素,(S)-(-)-spirobrassinin [(-)-4]及其恶唑啉类似物螺恶唑啉(11)的立体化学研究。通过SOCl(2)或MsCl介导的二西br子素[(+/-)-8]的环化反应合成外消旋螺孢子素[(+/-)-4]。用CSCl(2)处理(3-羟基氧代吲哚-3-基)甲基氯化铵[(+/-)-9],然后将所获得的螺恶唑烷硫酮(+/-)-10甲基化,得到螺恶唑啉[(+/-)- 11]。通过(S)-(-)-1-苯乙基异氰酸酯(12)衍生化,色谱分离非对映异构酰胺13、14或15、16实现对(+/-)-4和(+/-)-11的对映拆分,并用CH(3)ONa进行切割。天然(S)-(-)-4中立体异构中心的绝对构型是由激子得出的,通过CD方法计算得出,并且通过X射线晶体学分析明确证实了(+)-和(-)-4的1- [1'S,4'R-(-)-樟脑酰基]衍生物[(-)-19和(-)-20]