yield a cis-2,5-disubstituted tetrahydrofuran, thus providing a powerful illustration of a stereodirecting effect first noted by Rychnovsky and Bartlett. The tetrahydrofuran was transformed into a subunit suitable for incorporation into the shellfish toxin gymnodimine.
[反应:请参见文字]。已显示双-(2,6-二
氯苄基)醚经过高效且高度立体选择性的分子内
碘醚化反应,生成顺式2,5-二取代的
四氢呋喃,因此提供了Rychnovsky和Bartlett首先指出的立体定向作用的有力例证。将
四氢呋喃转化为适合掺入贝类毒素裸子草胺的亚基。