Regio- and Stereoselective Alkylation of Pyridine-<i>N</i>-oxides: Synthesis of Substituted Piperidines and Pyridines
作者:Deepak Kumar Barange、Magnus T. Johnson、Andrew G. Cairns、Roger Olsson、Fredrik Almqvist
DOI:10.1021/acs.orglett.6b02667
日期:2016.12.16
Regio- and stereoselective addition of alkyl Grignard reagents to pyridine-N-oxides gave C2-alkylated N-hydroxy-1,2,5,6-tetrahydropyridines and trans-2,3-disubstituted N-hydroxy-1,2,5,6-tetrahydropyridines in good to excellent yields. These intermediates were aromatized or alternatively reduced in one-pot methodologies for efficient syntheses of alkylpyridines or piperidines, respectively. These reactions
将烷基格氏试剂的区域和立体选择性加成到吡啶-N-氧化物上,得到C2-烷基化的N-羟基-1,2,5,6-四氢吡啶和反式-2,3-二取代的N-羟基-1,2,5, 6-四氢吡啶类化合物的产率高至优异。将这些中间体分别芳香化或一锅法还原,以分别有效地合成烷基吡啶或哌啶。这些反应具有广泛的底物范围和短的反应时间。