Gold-Catalyzed<i>endo</i>-Cyclizations of 1,4-Diynes to Seven-Membered Ring Heterocycles
作者:Kristina Wilckens、Marcus Uhlemann、Constantin Czekelius
DOI:10.1002/chem.200901702
日期:2009.12.14
endo‐Rule for gold: A highly endo‐selective gold‐catalyzed cycloisomerization of 1,4‐diynes was developed. By employing electron‐rich phosphines and N‐heterocyclic carbenes as ligands, a number of 1,4‐diynes could be cyclized in a desymmetrizing fashion to form dihydrodioxepines and enantiomerically enriched tetrahydrooxazepines (see scheme).
内金的规则:开发了高内选择性的金催化的1,4-二炔的环异构化反应。通过使用富含电子的膦和N-杂环卡宾作为配体,可以将多个1,4-二炔以脱对称形式环化,形成二氢二氧杂庚烷和对映异构体富集的四氢氧杂氮杂烷(参见方案)。