Ortho-selectivity in the nucleophilic aromatic substitution (SNAr) reactions of 3-substituted, 2,6-dichloropyridines with alkali metal alkoxides
作者:Jeremy L. Yap、Kellie Hom、Steven Fletcher
DOI:10.1016/j.tetlet.2011.06.007
日期:2011.8
basicities favour substitution of the chlorine ortho to the 3-substituent by alkali metal alkoxides. We present convincing evidence that coordination of the alkali metal counter-ion to the 3-substituent (nitro, ester, amide) is the origin of the ortho-selectivity to give a cyclic, six-membered transition state. Excellent ortho-selectivities (⩾98:2) for secondary and tertiary alkoxides were realized with