A study on the BF3-directed lithiation of 2-picoline and 2,3-lutidine
作者:Jaspreet S. Dhau、Amritpal Singh
DOI:10.1016/j.jorganchem.2013.09.013
日期:2014.1
The lithiation of 2-picoline (1a) and 2,3-lutidine (1b) in diethyl ether has been investigated with and without prior complexation with BF3. The reactions of the BF3 adduct of these moieties (2a and 2b) with lithium diisopropylamide (LDA) and subsequent trapping with benzaldehyde or dimethyl disulfide gave products corresponding to exclusive lithiation at the a-methyl carbon. The yields obtained with these reactions were far superior to that obtained with the lithiation of uncomplexed 1a and 1b. The dilithiation of 2a and 2b has also been investigated and a convenient and efficient synthesis of the diiodo derivatives of 1,2-bis(pyridin-2-yl) ethane has been provided. (C) 2013 Elsevier B. V. All rights reserved.
The Methyl Group as a Source of Structural Diversity in Heterocyclic Chemistry: Side Chain Functionalization of Picolines and Related Heterocycles
作者:Victor Mamane、Emmanuel Aubert、Yves Fort
DOI:10.1021/jo071209z
日期:2007.9.1
The reaction of 2-picoline at the methyl group with NDA and KDA followed by dimethyldisulfide trapping furnished, respectively, dithioacetals and trithioortho esters with high selectivity. The method was successfully applied to other methyl-substituted pyridines, quinolines, and pyrazines. Dithioketals were prepared by a one-pot procedure involving the reaction of metalated 2-picoline with 2 equiv