Novel approach to the ansamycin antibiotics macbecin I and herbimycin A. A formal total synthesis of (+)-macbecin I
作者:Stephen F. Martin、Jeffrey A. Dodge、Laurence E. Burgess、Chris Limberakis、Michael Hartmann
DOI:10.1016/0040-4020(95)01107-2
日期:1996.2
The asymmetric syntheses of 25 and 29, which constitutes the C(3)–C(15) segment of the stereochemically complex ansa chain of (+)-macbecin I (1) and herbimycin A (2), respectively, have been achieved. The approach features the furan-hydropyranone transformation 9→10 followed by stereoselective introduction of substituents onto the conformationally-biased hydropyran ring of 10 to give 17. Extension
已实现25和29的不对称合成,分别构成(+)-macbecin I(1)和除草霉素A(2)的立体化学复杂ansa链的C(3)–C(15)段。该方法的特征是呋喃-氢吡喃酮转化9→10,然后将取代基立体选择性地引入构象偏向的氢吡喃环10上,得到17。侧链17的延伸导致枢轴中间件22,该中间件被细化为25和29。25羧基末端的重新官能化提供了26,通过立体选择性地将芳基锂加到内醇30中转化为32。32的结构通过将其转化为34来建立,该结构是Baker 1的总合成中的高级中间体,从而完成了光学纯(+)-macbecin I(1)的形式合成。