Highly regioselective Friedlander annulations with unmodified ketones employing novel amine catalysts: Syntheses of 2-substituted quinolines, 1,8-naphthyridines, and related heterocycles

被引:142
作者
Dormer, PG [1 ]
Eng, KK [1 ]
Farr, RN [1 ]
Humphrey, GR [1 ]
McWilliams, JC [1 ]
Reider, PJ [1 ]
Sager, JW [1 ]
Volante, RP [1 ]
机构
[1] Merck & Co Inc, Dept Proc Res, Rahway, NJ 07065 USA
关键词
D O I
10.1021/jo026203i
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
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 favoring the 2-substituted products. The most reactive and regioselective catalyst was the bicyclic pyrrolidine derivative, TABO (1,3,3-trimethyl-6-azabicyclo[3.2.1] octane), yielding 1,8-naphthyridines with as high as 96:4 regioselectivity. Regioselectivity increased with slow addition of the methyl ketone substrate to the reaction mixture, and was positively related to temperature. Isolated yields of single regioisomers were typically 65-84%, while observed regioselectivities were greater than or equal to90:10 for 1,8-naphthyridines and greater than or equal to84:16 for quinolines.
引用
收藏
页码:467 / 477
页数:11
相关论文
共 41 条