Question

Mechanism. While the reaction carried out in lab used potassium hydroxide as the catalyst, many other catalysts have been developed to increase regioselectivity and stereoselectivity in aldol condensations. One small molecule catalyst commonly used is proline, a naturally occurring amino acid The mechanism involves the initial formation of an enamine; predict the structure of this enamine intermediate (intermediate A), and draw the mechanism for the conversion of intermediate A to а. intermediate B. Helpful Hint: The formation of the new carbon-carbon bond occurs at the same time as protonation to form the alcohol b. Draw the mechanism for the hydrolysis of intermediate B to form the final product and regenerate the catalyst н он он (0.2-0.3 eq.) + H DMSO-H20 R он intermediate A RT intermediate B O= o:

Answer 1

Answer tré dil kot je de la noge bir Mechanism -H2O LA yield Protom, ali i nature in a Achar Proton abstraction from Keetone is the major product because in acetone the two methyl group has tI effect, they reduce the electrophilic Character of the carbon atom. This is the reason why the reactivity of the acetone decreases in the addition reaction of pooton abstracted aldehyde with acetone. In case of aldehyde, there is only one alkyl group. Thus its carbon atom in the carbonyl group is more an electrophilic than in the case of acetone.

einde van het alleen OM DMSO - 11,0 in intermediale A intermediale B Mechanism Yule ya sehemu H yoo HO 40' ROHO WO allack intermediale A CO O intermediate B