Question

Preparation of an a,b-unsaturated ketone via Michael and Aldol reactions

The carbon next to the carbonyl (C=O) carbon is called the a carbon and the carbon next to the a carbon is called the b carbon. An a,b-unsaturated car- bonyl compound is a carbonyl compound (aldehyde, ketone, ester, etc.) that has a multiple (double or triple) bond between the a carbon and the b carbon.

As part of your post-lab report, analyze your spectra. “Analyze” doesn’t mean just assigning the peaks: it

As part of your post-lab report, analyze your spectra. “Analyze” doesn’t mean just assigning the peaks: it means as-

means assigning and discussing the basis of your assignments. For example, the IR of the product should signing and discussing the basis of your assignments. For example, the IR of the product should exhibit two promi-

exhibit two prominent peaks corresponding to carbon–oxygen double bond stretching, one belonging to

nent peaks corresponding to carbon–oxygen double bond stretching, one belonging to the ester and the other to the

the ester and the other to the ketone: How do you know which is which?

ketone: How do you know which is which?

300 280 260 1240 220 200 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 11 (ppm) 3.5 3.0 2.5 2.0 1.5 1.0

Answer 1

In the given IR Spectrum there are two values given for two peaks of coabonyl steaching Frequencies region shear about 1200 cm! Among these two values one is 1656.16 cm & another is 1732.69 cm in which 1656. Cirt is for the ketone and 1732 cmt for the ester carbony! Sreaching frequency, because estes has relatively higher steaching frequency than Ketone due en inductive effect of exveena OF OR group of estes molecule. that pull election density of oxygen of carbonyl group towords itself and make c=o bond more stronger than ketone caobonyl Cobond. So has higher c=o spreaching frequency than ketone - ketone & Batů – u a trove our OR ketone RRR ester R ediou of Inductive effect of -OR score of coopgroup Make Cro bond Stinger so it has higher Ir than ditter Lt Ketone this does not happen with Ketone.