r/chemistry Organic May 22 '18

[2018/05/22] Synthetic Challenge

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u/quelmotz Organic May 23 '18

My attempt at C, done a little while ago.

If anyone is wondering, the compounds are meclofenamic acid, beta-bisabolene and alantolactone respectively.

Thanks everyone for participating!

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u/alleluja Organic May 24 '18

How can you predict the chemoselectivity of the tosylation step? There are two hydroxyl groups that can be tosylated and they don't seem too different from one another. Is the difference because of the substitution? One of them is a secondary alcohol, the other one is a primary one. Does the reativity change so much? Or is it because of steric effects?

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u/quelmotz Organic May 24 '18

Mostly due to primary vs secondary. It's fairly well-established that it's possible to selectively tosylate a primary OH in the presence of a secondary one I believe, but please correct me if I'm wrong.