Organic Chemistry Questions

suggested using an enamine intermediate because it's a weaker base (it's neutral!!) and so more likely to act as a Michael donor (1,4- addition)

if nucleophile adds reversibly, the 1,4-overall thermodynamic product dominates (note resonance in 1,4 enolate)

NaOH over H2O, aldol addition gives a beta-hydroxy aldehyde or ketone

the initial enol is the result of 'conjugate' or 1,4-addition. The enol tautomerizes to the more stable keto form

aldol reaction occurs. The product (a β-hydroxycarbonyl) features both aldehyde and alcohol groups

has a lower activation energy for formation (carbonyl has larger delta plus). If nucleophile adds irreversibly, the 1,2-kinetic product dominates

gives cyclohexenones and is a Michael addition followed by internal Aldol condensation

the formation of a conjugated (stable) pi system. Aldol addition products are often difficult to isolate, even at low T

more acidic than an aldehyde, ketone, or ester, because its conjugate base is stabilized (resonance) by the presence of the two carbonyls

Two different esters (or an ester and a ketone!) can be used, but one should have no alpha hydrogens, for example a benzoate, formate, carbonate, or oxalate

weakly acidic, hence esters can be deprotonated to give an ester enolate anion, which is a strong nucleophile

an ester molecule (with electrophilic carbonyl group) undergoes nucleophilic acyl substitution by an ester enolate

see what groups are added to the acetic acid product, then alkylate malonic ester with R-X and R-X, hydrolyze, decarboxylate

aldol addition plus alsol condensation, gives alpha beta unsaturated aldehyde or ketone

retro aldol mechanism can work, carbanion leaving group acceptable due to resonance stabilization of enolate, done by breaking alpha beta bond

enolates. Kinetic product forms faster, thermodynamic is more stable (more substituted c=c; favored at high T)

top arrow is aldol addition, bottom arrow is aldol condensation

combine two or more molecules, often with the loss of a small molecule such as water, an alcohol, CO2, or N2

is deprotonated in a strongly exothermic step (strong base present !!!), which DRIVES THE REACTION forwards

electrophilic carbon atoms. The beta-C is electrophilic because it shares the δ+ of the carbonyl C (resonance).