Application of Lewis Acid Catalyzed Tropone [6+4] Cycloadditions to the Synthesis of the Core of CP-225,917
作者:Ljubomir Isakovic、James A. Ashenhurst、James L. Gleason
DOI:10.1021/ol016814h
日期:2001.12.1
The carbocyclic core of CP-225,917 and CP-263,114 is accessible through the [6+4] cycloaddition of a tropone with a 2-substituted cyclopentadiene. Examination of this reaction has revealed for the first time that this cycloaddition process is catalyzed by Lewis acids, including lanthanide triflates. Cycloadditions of several mono-, di-, and trisubstituted tropones with 2-silyloxycyclopentadienes using
CP-225,917和CP-263,114的碳环核可通过将6-环己二烯与2个取代的环戊二烯进行[6 + 4]环加成而获得。该反应的检验首次揭示该环加成过程是由路易斯酸,包括镧系三氟甲磺酸酯催化的。发现使用ZnCl(2)催化与2-甲硅烷氧基环戊二烯的几个单,二和三取代的托环酮的环加成反应可进行良好的收率,在许多情况下,具有非对映选择性。随后转化为CP分子的核心涉及三环二酮的位点选择性Baeyer-Villiger氧化,然后进行同消除过程。[反应:看文字]