Second Generation Synthesis of C27−C35 Building Block of E7389, a Synthetic Halichondrin Analogue
作者:Yu-Rong Yang、Dae-Shik Kim、Yoshito Kishi
DOI:10.1021/ol9016589
日期:2009.10.15
A practical method is reported to synthesize E7389 C27−C35 building block 13 from 1,2-O-isopropylidene-α-d-5-deoxyglucurono-6,3-lactone (3). This synthesis relies on two key processes: (1) C34/C35-diol is introduced via asymmetric dihydroxylation with dr = 3:1, with the undesired C34-diastereomer effectively removed by crystallization of 11, and (2) the C30 PhSO2CH2 group is introduced stereoselectively
据报道,从 1,2 - O-异亚丙基-α- d -5-脱氧葡萄糖醛酸-6,3-内酯合成 E7389 C27-C35 结构单元13的实用方法( 3 )。该合成依赖于两个关键过程:(1) 通过不对称二羟基化引入 C34/C35-二醇,dr = 3:1,通过11的结晶有效去除不需要的 C34-非对映异构体,以及 (2) C30 PhSO 2 CH在 Crabtree 催化剂的存在下,通过12 的氢化以立体选择性 (>100:1) 引入2基团。报告的合成实际上没有色谱分离。