Neighbouring group participation by carbonyl groups in ester hydrolysis

Neighbouring group participation by carbonyl groups in ester hydrolysis, 28, 171 Nitration, nitrosation, and halogenation, diffusion control and pre-association in, 16, 1 Nitrosation, mechanisms, 19, 381... 

Neighbouring Group Participation by Carbonyl Groups in Ester Hydrolysis... 

Ester hydrolysis, neighbouring group participation by carbonyl groups in, 28, 171... 

By 1903, Emil Fischer had already appreciated that a proximate nucleophile can accelerate the rate of cleavage of an otherwise unreactive amide. Adaptation of such neighbouring group participation to relay deprotection is easy all that is required is a protecting group with a latent hydroxyl or amino function within easy bonding distance of the amide carbonyl, as illustrated in Scheme 8.27 by the reduction of the o-nitrophenylacetamide 27,1. The theme is capable of extensive variation. For example, 2-((/er/-butyldiphenylsilyloxy)methyl]benz-amides (27.2), 2-(acetoxymethyl)benzamides (273) and 3-methyl-3-(2,4,5-tri-methyl-3,6-dioxo-cycIohexa-l,4-dienyl) butyramides (27.4) all have latent hydroxyl nucleophiles that are released by silyl ether cleavage, ester hydrolysis and quinone reduction, respectively. 

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