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CHAPTER 21 889 
 
 
 
(f) The conjugate base of diethyl malonate functions as a 
nucleophile and attacks the  position of the -
unsaturated nitrile. The resulting intermediate is 
converted back into a nitrile upon acid work-up, giving 
the following product: 
 
 
 
(g) The conjugate base of diethyl malonate functions as 
a nucleophile and attacks the acid anhydride to give a 
tetrahedral intermediate, which expels an acetate ion to 
reform a carbonyl group (via a nucleophilic acyl 
substitution reaction): 
 
 
 
This compound is deprotonated under these conditions 
(by the acetate ion, which can function as a base), which 
serves as a driving forced to push the reaction to 
completion. Then, acid workup gives the proton back, 
regenerating the product shown above. 
 
(h) The conjugate base of diethyl malonate functions as 
a nucleophile and attacks the  position of the -
unsaturated nitro compound. The resulting intermediate 
is converted back into a nitro compound upon acid work-
up, giving the following product: 
 
 
 
21.85. A Robinson annulation is comprised of a Michael 
addition, followed by an intramolecular aldol 
condensation, as shown: 
 
 
 
21.86. A Robinson annulation is comprised of a 
Michael reaction, followed by an intramolecular aldol 
condensation. To determine the starting materials 
necessary to prepare the desired product via a Robinson 
annulation, we draw the following retrosynthetic 
analysis: 
 
 
These two steps do not represent two separate reactions. 
A Robinson annulation can be performed in one reaction 
flask, as shown in the following forward scheme: 
 
 
 
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