[orgo814]

I am usually good at converting from Newman projections to bond line... At least in the regular intro organic courses. However, when I use the Felkin Anh model (which I know how to generate the Newman projection), whenever I translate it to the bond line formula I am getting an incorrect stereochemistry. I'm not sure what's different about the Felkin Anh when it comes to translating to bond line but does anyone have a trick on how to do this? I can't use models on the exams so I need to know how to do this in 2D. Thank you.

[Dan]

Do you have a specific example of one you got wrong? Explain what you did, and then we can see where you went wrong.

There are two ways to get the wrong answer - It's not clear whether the problem is a mistake in conversion from Newman projection or a mistake using the Felkin-Ahn model to predict facial preference.

[Doc Oc]

I agree with Dan that more specific examples would be helpful.

That being said, one of the critical things with Felkin-Ahn is that after you've predicted the configuration you need to rotate the parts so that the longest carbon chain ends up anti-periplanar. If you aren't doing this you won't get the correct absolute configuration.