Conversion of 2-Alkylcinnamaldehydes to 2-Alkylindanones via a Catalytic Intramolecular Friedel−Crafts Reaction
作者:Gary B. Womack、John G. Angeles、Vincent E. Fanelli、Christie A. Heyer
DOI:10.1021/jo070952o
日期:2007.8.31
3-arylpropanoic acids or halides requires the use of noncatalytic acid promoters. In the presence of 5−10 mol % FeCl3, in situ generated dimethyl acetals of (E)-2-alkylcinnamaldehydes cyclize to 1-methoxy-2-alkyl-1H-indenes in good-to-high yields. The 1-methoxyindenes were converted in high yield into 2-alkylindanones by treatment with triethylamine, to effect isomerization to the isomeric enol ethers
通过3-芳基丙酸或卤化物的分子内酰化制备茚满酮需要使用非催化酸促进剂。在5-10摩尔%FeCl 3的存在下,原位生成的(E)-2-烷基肉桂醛的二甲基乙缩醛以良好或高收率环化为1-甲氧基-2-烷基-1H-茚。通过用三乙胺处理,将1-甲氧基茚高产率地转化为2-烷基茚满酮,以进行异构化成异构的烯醇醚,然后进行酸催化的水解。因此,开发了一种催化的分子内弗里德尔-克来福特反应,其由2-烷基肉桂醛生成2-烷基茚满酮。