作者:Jaspreet S. Dhau、Amritpal Singh、Yoganjaneyulu Kasetti、Sonam Bhatia、Parsad V. Bharatam、Paula Brandão、Vítor Félix、Kamal N. Singh
DOI:10.1016/j.tet.2013.10.026
日期:2013.12
The BF3-directed lithiation of 3-chloro- and 3-bromopyridine (1a and 1b, respectively) has been investigated. The reactions of 3-chloro- or 3-bromopyridine–BF3 adduct with LDA (1.3/1.1 equiv) followed by quenching with benzaldehyde or iodine exclusively gave the C-2 substituted products. However, when 2.2 equiv of LDA and dimethyl disulfide was used, a C-6 substituted product was obtained. Dilithiation
研究了3-氯吡啶和3-溴吡啶的BF 3定向锂化(分别为1a和1b)。3-氯或3-溴吡啶-BF 3加合物与LDA(1.3 / 1.1当量)的反应,然后用苯甲醛或碘淬灭,仅得到C-2取代的产物。然而,当使用2.2当量的LDA和二甲基二硫化物时,获得了C-6取代的产物。在有和没有BF 3络合的情况下,已经研究了1a和1b的双锂化。Li⋯F(BF 3)相互作用的作用已通过实验和DFT计算进行了研究。