作者:Maliha Uroos、William Lewis、Alexander J. Blake、Christopher J. Hayes
DOI:10.1021/jo101691n
日期:2010.12.17
(R)-(+)-limonene oxide using a hetero-Diels−Alder cycloaddition as a key step. The key Diels−Alder cycloaddition proceeds with endo-selectivity (2:1, endo/exo) in quantitative yield, and the two diastereomeric spirochroman products are isolable, stable products. Furthermore, the exo- and the endo-hetero-Diels−Alder cycloaddition products (2 and 7) can be oxidized with m-CPBA to produce (+)-cymbodiacetal (1) and the
使用杂Diels-Alder环加成作为关键步骤,从(R)-(+)-柠檬烯氧化物完成了(+)-环乙缩醛(1)的全合成。关键的Diels-Alder环加成反应以定量产率进行内选择性(2:1,endo / exo),并且两个非对映异构螺吡喃衍生物是可分离的,稳定的产物。此外,exo-和内-杂-Diels-Alder环加成产物(2和7)可以用m -CPBA氧化,生成(+)-cymbodiacetal(1)和C 2-对称的双半缩醛结构8分别。异构体半缩醛9在两个氧化反应中产生。使用X射线晶体学确认了(+)-cymbodiacetal(1),其C 2对称非对映异构体8和异构体半缩醛9的结构。