Highly Regioselective Friedländer Annulations with Unmodified Ketones Employing Novel Amine Catalysts: Syntheses of 2-Substituted Quinolines, 1,8-Naphthyridines, and Related Heterocycles
作者:Peter G. Dormer、Kan K. Eng、Roger N. Farr、Guy R. Humphrey、J. Christopher McWilliams、P. J. Reider、Jess W. Sager、R. P. Volante
DOI:10.1021/jo026203i
日期:2003.1.1
Catalysts were evaluated on the preparation of 2-substituted quinolines, 1,8-naphthyridines, and chromone derivatives from unmodified methyl ketones and o-aminoaromatic aldehydes. While oxide catalysts yielded the 2,3-dialkyl substituted products, cyclic secondary amines provided the 2-alkylsubstutited products regioselectively. In particular, pyrrolidine derivatives provided the highest regioselectivity
对由未改性的甲基酮和邻氨基芳族醛制备2-取代的喹啉,1,8-萘啶和色酮衍生物的催化剂进行了评估。尽管氧化物催化剂产生了2,3-二烷基取代的产物,但环状仲胺区域选择性地提供了2-烷基取代的产物。特别地,吡咯烷衍生物提供了对2-取代产物有利的最高区域选择性。最具反应性和区域选择性的催化剂是双环吡咯烷衍生物TABO(1,3,3-三甲基-6-氮杂双环[3.2.1]辛烷),产生1,96-萘啶,具有高达96:4的区域选择性。随着向反应混合物中缓慢加入甲基酮底物,区域选择性增加,并且与温度成正相关。单一区域异构体的分离产率通常为65-84%,