Question

7. Give two examples of a ketone that would react with a nucleophile at a higher rate than acetone, and explain why it would be more reactive. (4 pts) Acetone

Answer 1

Example 1:. 1,1,1- trifluoro acetone

Example 2:. 1- chloro acetone

Detailed explanation has been given in the pictures attached.
The carbonyl carbon of an aldehyde on kelone is electrophilic due to the more elecionegālive nalīre el oxygencompared to carbon. Thus, the carbonyl (c=0) group practically remains in change Separaled form (28) due to this eleclionegatively difese difference. In presence of external reagent like nucleophile, the A-bond between carbon and oxygen gels easily polarised and the nucleophile joins the carbonyl star carbon. From the above equation we see greater the electrophilicily of the carbonyl C-atom fastos will be the wo attack and hence faster will be the rate of reaction.

For acetone, Chc=0 it is due to the CHE' positive inductive effect by 2 snelkyl groups the elechophilicity of carbonyl carbon is decreased and also hence rate of reaction wila a nucleophile is also less. Nolé : Positive inductive. Effect (+1-effect) is shown Ha group attached to the cambon is less elechonegative than hydrogen, and hence ét donales elechoon to the carbon-systeme Hi exe-o [+5+ effect in acetane]. Hac Thus, lo answer the given question if we can increase the elechnophilicilo of l-ałom then reaction rate will increase. This can be achieved by attaching elechon will drawing groups which exhibit negative inductive effect

Note : Negative inductive effect (-I effect) is shown 4 a group is mone electro megative than fydnagin and theus wilk dnaws election from cambon chain tocsands itself Hence, example 1: Folio [1,1,1- bifluoroacetone] FH Since, F is highly elechonegative it wilhdrawa plechon density i.e. exhəbils – 1-effect. This causes the carbonyl carbon lő be mone electron deficient and hence more susceptible to mucleophilie allack. Thus, reaction rate towanos nucleophiles becomes faster than acetone. example 2 : * = [ 1-Chlono acetone 7 Similarly, a being mone electronegative than Hi exhibits -I effect and thus this makes the

mone Carbonyl carbon, electrophilie than acetone and thes nucleophilic reaction is faster than acetone. Note D As Cl is larger in size than F, only latom of H- has been replaced by Cl in onder to avoid any steric crowding. For 1,1,1- bifuimoacktone as F is smaller in size all the 3t has been replaced by F to enhance the carbonyl carbon electrophilieity