Nucleophilic aromatic mechanism strategies

Going over the basics and mechanisms of nucleophilic substitution reactions Mastering mechanisms of elimination/addition reactions Determining synthesis strategies for aromatic systems... 

A simple one-pot strategy for the synthesis of differently substituted quinoxalines from 1,2-aryl diamines and 2-bromomalonic ester at room temperature (Scheme 65) xmder solvent- and catalyst-free conditions has been investigated by Haidar et al. [95]. The mechanism followed is nucleophilic substitution, amide formation, followed by in situ oxidative aromatization. The compoxmd 54a, a key synthetic intermediate for the synthesis of a 5-HT3 receptor antagonist, could be effectively synthesized by this reaction protocol. 

Jun et al. demonstrated a Rh(I)-catalyzed cyclization of an N-benzyl aromatic ketimine with diphenylacetylene to provide isoquinoline 44 [27]. The chelation-assisted C-H activation strategy was employed for the first time for isoquinoline synthesis. However, the reaction required a high temperature (150 C) and led to two different isoquinoline derivatives 44 and 44. Based on the experimental results, the authors proposed a plausible reaction mechanism that involved ortho-alkenylation, 6. r-electrocyclization, intermolecular nucleophilic substitution, and dehydrogenative aromatization (Eq. (5.43)). 

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