A Case Study: The Nitro Group. As an example, the class designation of the nitro function is determined by an evaluation of the parent function, its nitronic acid tautomer, as well as conjugate acid and base 14 and 15 H-tautomet conjugate base conjugate base N一CH2R +N■cHR nitronic acid nitronate anion. 14 From the collection of transformations of the nitro group one finds that the dominate mode of reac tivity of the nitronate anion 14 is that of a G-function while the protonated nitronic acid 15 mirrors the re- activity of an E-functic The dominate polar site reactivit D FG-C The typical behavior of nitronate anions 14 is summarized in the representative transformations provided in Scheme VI. These moderately nucleophilic species, although they are not readily alkylated readily undergo aldol and conjugate addition reactions Scheme vi selected reactions of the nitronate anion oa The charge affinity pattern: NCH This reactivity pattern may be extended via conjugation It is no surprise that the charge affinity pattern of this fg may be extended by conjugation, an a,B-unsaturated nitro compounds readily participate in conjugate addition reactions(Scheme vil) Scheme vii selected reactions of the nitronate anion The Reaction 只、c=cH Nu(-) CH2-CH-Nu The charge affinity pattern Nitro aromatics. The resonance feature which has been exploitedFunctional Group Classification page 6 A Case Study: The Nitro Group. As an example, the class designation of the nitro function is determined by an evaluation of the parent function, its nitronic acid tautomer, as well as conjugate acid and base 14 and 15. N O O CH2R N HO O CHR N O O CHR N HO HO CHR + – – + + – – H-tautomer conjugate base conjugate base + nitronic acid nitronate anion, 14 15 From the collection of transformations of the nitro group one finds that the dominate mode of reac￾tivity of the nitronate anion 14 is that of a G-function while the protonated nitronic acid 15 mirrors the re￾activity of an E-function. N HO HO CHR FG C N FG C O O CHR 15 14 (+) + + – – The dominate polar site reactivity (–) The typical behavior of nitronate anions 14 is summarized in the representative transformations provided in Scheme VI. These moderately nucleophilic species, although they are not readily alkylated, readily undergo aldol and conjugate addition reactions. + N O + N –O –O –O CH2–R CH–R + N O –O El + N O –O R CH–R + N O –O CH2–R Scheme VI Selected Reactions of the Nitronate Anion base pKa ~ 10 El(+) The Reaction: ● ● – The charge affinity pattern: (–) ■ This reactivity pattern may be extended via conjugation: It is no surprise that the charge affinity pattern of this FG may be extended by conjugation, and a,b-unsaturated nitro compounds readily participate in conjugate addition reactions (Scheme VII). R H N X: R H N X: R H N X: + N O –O CH CH R + N O –O CH2 CH Nu R + N O –O CH CH R + N –O –O CH CH R + N –O O Scheme VII Selected Reactions of the Nitronate Anion X = OR, NR2 (–) (–) (+) (+) ■ The resonance feature which has been exploited: Nu(–) (–) (+) The Reaction: The charge affinity pattern: (–) (+) + (+) (+) Nitro aromatics: (+) ✔✔