Abstract

Acetals of dimethyl phenyl- and heteroaryl-α-hydroxymethanephosphonates were deprotonated to generate carbanions, which enter the vicarious nucleophilic substitution (VNS) of hydrogen in aromatic nitro compounds to form 4-nitrobenzhydrylphosphonates and α-heteroaryl-4-nitrobenzylphosphonates. Similarly acetals of cyano­hydrins of heteroaromatic aldehydes (furfural and 2-formylthiophene) react to form heteroaryl 4-nitroarylacetonitriles. The anion of the hemiacetal of acetaldehyde is an efficient leaving group in the base-induced β-elimination step – the crucial step in the VNS reaction. The reaction selectively occurred at the para-position to the nitro group.

中文翻译：

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通过取代亲核取代（VNS）反应简单合成硝基二苯甲基膦酸二甲酯和杂芳基硝基芳基乙腈

摘要

将二甲基苯基和杂芳基-α-羟基甲烷膦酸酯的缩醛去质子化以生成碳负离子，碳负离子进入芳族硝基化合物中的氢的亲核取代基（VNS），形成4-硝基苯甲酰基膦酸酯和α-杂芳基-4-硝基苄基膦酸酯。类似地，杂芳族醛（糠醛和2-甲酰基噻吩）的氰醇缩醛反应形成杂芳基4-硝基芳基乙腈。乙醛半缩醛的阴离子是碱诱导的β-消除步骤（VNS反应的关键步骤）中的有效离去基团。该反应选择性地发生在硝基的对位。