Cyanide Anion as a Leaving Group in Nucleophilic Aromatic Substitution: Synthesis of Quaternary Centers at Azine Heterocycles
作者:Alexander D. Thompson、Malcolm P. Huestis
DOI:10.1021/jo302307y
日期:2013.1.18
Nucleophilic aromatic substitution of 2- or 4-cyanoazines with the anions derived from aliphatic α,α-disubstituted esters and nitriles leads to displacement of the cyanide function. Enabling cyanides to be used as highly active leaving groups in SNAr reactions provides additional flexibility in starting materials for synthesis. We show that, in many cases, the cyanide leaving group is displaced preferentially
用衍生自脂族α,α-二取代的酯和腈的阴离子对2-或4-氰基嗪进行亲核芳族取代会导致氰化物官能团的置换。使氰化物能够在S N Ar反应中用作高活性离去基团,为合成原料提供了额外的灵活性。我们表明,在许多情况下,氰化物离去基团在卤素存在下优先被取代。所得的杂芳基碘化物,溴化物和氯化物随后可用作进一步化学多样化的处理方法。
Decarboxylative trifluoromethylthiolation of pyridylacetates
Decarboxylative trifluoromethylthiolation of lithium pyridylacetates was achieved using N-(trifluoromethylthio)benzenesulfonimide as the electrophilic trifluoromethylthiolation reagent. The reaction afforded the corresponding trifluoromethyl thioethers in good yield. Furthermore, the preparation of lithium pyridylacetates by saponification of the corresponding methyl esters and subsequent decarboxylative
Syntheses of substituted pyridines and fluorinated compounds, which are often pharmaceutical targets, are important objectives in organic chemistry. Herein, we found that decarboxylative fluorination of lithium 2‐pyridylacetates occur under catalyst‐free conditions. The phenomenon can be applied to one‐pot transformation of substitutedmethyl 2‐pyridylacetate to 2‐(fluoroalkyl)pyridine by decarboxylative