Total synthesis of the macrolide (+)-aspicilin by an asymmetrically catalyzed macrocyclization of an ω-Alkynal ester
作者:Wolfgang Oppolzer、Rumen N Radinov、Jef De Brabander
DOI:10.1016/0040-4039(95)00351-c
日期:1995.4
ω-Alkynal ester 3, prepared from (S)-propylene oxide 4, yields the macrocyclic (6R)-allylic alcohol 2 (60% yield, 83% d.e.) in one operation via monohydroboration, boron/zinc-transmetalation and (−)-DAIB “catalyzed” intramolecular alkenylzinc/aldehyde addition. Introduction of the C(2)–C(3) double bond by selenoxide elimination (2 → 8), hydroxy-directed epoxidation (8 → 9), acetate assisted α-epoxide
ω-炔醛酯3,由(小号) -氧化丙烯4,得到大环(6 - [R )-烯丙基醇2(60%收率,83%德)在一次操作中通过monohydroboration,硼/锌-转移金属化和( - )-DAIB“催化”分子内链烯基锌/醛加成。通过亚硒酸酯消除(2→8),羟基定向环氧化(8→9),乙酸盐辅助的α-环氧化物开口(10→12)和酸性甲醇分解作用引入C(2)–C(3)双键+)-aspicilin(1)从4中获得22%的总产率。