Unusual Sterically Controlled Regioselective Lithiation of 3-Bromo-5-(4,4‘-dimethyl)oxazolinylpyridine. Straightforward Access to Highly Substituted Nicotinic Acid Derivatives
作者:Nicolas Robert、Anne-Laure Bonneau、Christophe Hoarau、Francis Marsais
DOI:10.1021/ol062556i
日期:2006.12.1
[Structure: see text] Lithiation of 5-bromonicotinic acid protected as secondary or tertiary amide as well as (4,4'-dimethyl)oxazoline with lithium amides is reported. The unusual C-2 and C-4 regioselective lithiation of 3-bromo-5-(4,4'-dimethyl)oxazolinylpyridine using LTMP versus LDA was observed, providing a new route to substituted nicotinic acid scaffolds. The methodology was applied to the synthesis
[结构:见正文]据报道,被保护为仲酰胺或叔酰胺的5-溴烟酸以及(4,4'-二甲基)恶唑啉被酰胺化锂。观察到使用LTMP与LDA的3-溴-5-(4,4'-二甲基)恶唑啉基吡啶的不寻常的C-2和C-4区域选择性锂化,为取代烟酸支架提供了一条新途径。该方法学被用于合成新的C-4和C-6芳基化的5-溴烟酸。