Question

Q6A) For the reaction below, draw the four possible products (excluding stereoisomers) that could arise from the aldol addition reaction shown. Hace + Base H3CO Me (strong enough for alpha deprotonation) 4 possible aldol addition products (excluding stereoisomers) в CH3 Q6B) How could this reaction be run as a directed aldol reaction to produce one product (excluding stereoisomers) where aldehyde A was converted into an enolate and attacked ester B? Circle this exact product in your answer to Q6A. Q6C) How many stereocenters are present in the starting material (A and B), and how many stereocenters are present in the direct aldol produce from Q6B?

Answer 1

Dr . Base sase 4 possible aldo addition rome possible proelnets Aldol reaction is the condensation of an aldehyde with an aldehyde or a kelone with a ketone of and as an aldehyde with a kelone having 2-hydrogens in presence of acid. I base catalyst to form - B-hydroxy carbonyl compounds R-č- CHE = -H OR CHg & CH3 This part should have X-hydrogene a-hydrogens x- hydrogens to : can take part in Aldol reaction generate an enolate NO X- hydsogens (cannot take part in . . .reaction) Aldol Answers : 07 HAH ] Vesonance enolate Stabilised anion

Ome H + O томе resonance Stabilised enolate anion. 0 . ( 1)

B-HI M . O OM Answer 6A 4- addition produits OM * OH O meo the one - By using LDA ( Lithium diisopropyl diamida) as a base, this Veaction can be sun as a directed aldol reaction to poodie One prochnet. Stereocenter . OH yen rome more M . O one Steveocenter No Stereocenters