13C NMR Question

[gotGino]

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So my question pertains to a question about 13C NMR. The figure in question is below, the stars indicate the carbons in question.

http://imageshack.us/photo/my-images/841/updownd.jpg/

In class, the professor said that the carbon on the left would be upfield, while the carbon on the right would be down field. I thought since oxygen was electronegative, it would pull electron density from the adjacent carbon, making it more downfield. It was said in class, however, that the oxygen would be providing electron density to that carbon, making it upfield. So I am a little confused on that part.

As for the carbon on the right, I wasn't sure what the explanation was, but since I am assuming that the oxygen is also pulling electron density from its adjacent carbon? I am not really sure.

 

[MedPR]

So my question pertains to a question about 13C NMR. The figure in question is below, the stars indicate the carbons in question.

http://imageshack.us/photo/my-images/841/updownd.jpg/

In class, the professor said that the carbon on the left would be upfield,while the carbon on the right would be down field. I thought since oxygen was electronegative, it would pull electron density from the adjacent carbon, making it more downfield.It was said in class, however, that the oxygen would be providing electron density to that carbon, making it upfield. So I am a little confused on that part.

As for the carbon on the right, I wasn't sure what the explanation was, but since I am assuming that the oxygen is also pulling electron density from its adjacent carbon? I am not really sure.

I haven't looked much at 13C NMR, but I'm pretty sure Phenyl rings typically result in a small upfield shift