Highly Stereoselective Total Syntheses of (±)-Chelidonine and of (±)-Norchelidonine by an Intramolecular<i>o</i>-Quinodimethane/Nitrostyrene-Cycloaddition
作者:Wolfgang Oppolzer、Christian Robbiani
DOI:10.1002/hlca.19830660415
日期:1983.6.15
Conversion of 2-bromomethylstyrene 22 and benzocyclobutenyl carbamate 28 to the benzophenanthridine alkaloids (±)-chelidonine (1, five steps, 25% from 28) and to (±)-norchelidonine (2, six steps, 24% from 28) are described. The key step 29 31 involves a highly regio- and stereocontrolled intramolecular Diels-Alder reaction of the (E)-quinodimethane 30.
描述了将2-溴甲基苯乙烯22和氨基甲酸苯并环丁烯基酯28转化为苯并菲啶生物碱(±)-鸟苷(1,五步,从28%降低到25%)和到(±)-去氯酮碱(2,六步,从28%降低到24%)。 。关键步骤29 31涉及(E)-喹二甲烷30的高度区域和立体控制的分子内Diels - Alder反应。