Stereocontrolled Synthesis of the C21–C38 Fragment of the Unnatural Enantiomer of the Antibiotic Nystatin A1
作者:Thilo Berkenbusch、Reinhard Brückner
DOI:10.1002/chem.200305540
日期:2004.3.19
The C(21)-C(38) fragment all-trans-41 of the unnatural enantiomer 1 of nystatin A(1) was prepared starting from the N-propionyl oxazolidinone 9. Aldol adduct ent-8 (ee > 96 %) derived in two steps was hydroborated with (thexyl)BH(2). Oxidative work-up and treatment with acid furnished delta-lactone 4. It contains the complete stereotetrade of the target molecule. The alpha,beta-unsaturated ester 28
制霉菌素A(1)的非天然对映异构体1的C(21)-C(38)片段全反式41是从N-丙酰恶唑烷酮9制备的。衍生的醛醇加合物ent-8(ee> 96%)分两步用(thexyl)BH(2)硼氢化。氧化后处理,并用酸提供的δ-内酯4进行处理。它包含目标分子的完整立体四聚体。在另外四个步骤之后获得了α,β-不饱和酯28。它应该是多种多元醇,多烯大环内酯的多烯部分的前体。说明从28和DIBAL获得的α,β-不饱和醛29在四个步骤中扩展了10个C原子,得到C(21)-C(38)段41。后一组转化包括区域选择性和立体选择性克莱森重新排列32-> 35。