Stereocontrol in a one-pot procedure for anionic oxy-Cope rearrangement followed by intramolecular aldol reaction
作者:Alistair P. Rutherford、Cameron S. Gibb、Richard C. Hartley、Jonathan M. Goodman
DOI:10.1039/b010138i
日期:——
β-hydroxycyclohexanones with up to three chiral centres have been synthesized in a stereocontrolled way using the novel anionic oxy-Cope (AOC) rearrangement of acyclic enol ethers. The first examples of compounds containing an aldehyde and an enol ether in a 1,5 relationship are reported. Stereocontrol in the cyclisation of these compounds by a 6-(enolendo)-exo-trig intramolecular aldol reaction has been
使用无环烯醇醚的新型阴离子氧化-Cope(AOC)重排,以立体控制方式合成了具有多达三个手性中心的外消旋β-羟基环己酮。报道了以1,5关系包含醛和烯醇醚的化合物的第一实例。已经研究了通过6-(烯醇烯)-外-trig分子内醇醛醇缩合反应对这些化合物进行立体控制的过程:β-羟基环己酮产物中的轴向羟基具有很高的立体选择性。AM1计算表明,在中间氧鎓离子中,轴向C-3羟基的氧原子与C-1处的贫电子碳之间存在稳定的静电吸引。≥87%的AOC重排通过一种椅子状的过渡态,产生β-羟基环己酮的5,6-抗立体化学。用氧气捕获AOC重排的烯醇化物产物会通过1,2-二氧杂环丁烷进行裂解。