A highly convergent total synthesis of the spiroacetal macrolide (+)-milbemycinβ1
作者:Steven V. Ley、Neville J. Anthony、Alan Armstrong、M.Gabriella Brasca、Trafford Clarke、David Culshaw、Christine Greck、Peter Grice、A.Brian Jones、Barry Lygo、Andrew Madin、Richard N. Sheppard、Alexandra M.Z. Slawin、David J. Williams
DOI:10.1016/s0040-4020(01)89182-1
日期:——
A highly convergent synthesis of the macrolide natural product milbemycin β1 is reported. The key features of this synthesis include the introduction of the C11-C15 side chain by selective ring opening of a symmetrical 1,4-pentane bis-epoxide (3) followed by reaction with the anion derived from the 2,3-trans-dimethyl-6-phenylsulphonyl pyran (2) to afford the “northern” C11-C25 fragment (33) of milbemycin
大环内酯类天然产物的高度会聚合成米尔倍霉素β 1报道。该合成的关键特征包括通过对称的1,4-戊烷双环氧化物(3)选择性开环引入C11-C15侧链,然后与衍生自2,3-反-二甲基的阴离子反应-6-苯基磺酰基吡喃(2),得到米尔倍霉素β中的“北部” C11-C25片段(33)1。经由新颖的去共轭乙烯基砜阴离子序列,将衍生的C 11 -C 25醛单元(37)与C 1 -C 10南部区域片段(5)偶联,得到包含天然产物的所有碳取代基的产物。最后操作涉及macrolactonisation和氧化硒随后推出的重要3,4-双键的SYN在剔除。在倒数第二个步骤中,在超声下用碘甲烷和氧化银(I)完成C-5羟基的甲基化反应。