Estrone: Borohydride Reduction

lizneth07 · Post by **lizneth07** » Sat May 31, 2008 8:35 pm

HELP!

I need to come up with a detailed mechanism of the reduction of estrone by sodium borohydride. The mechanism must explain the stereochemical route followed in the reaction, and I must comment on the stereospecificity of this reaction.

Can someone guide me through this please?

Zedekiah · Post by **Zedekiah** » Sun Jun 01, 2008 10:06 am

Estrone is reduced by sodium borohydride to form estradiol.

This may help with some of the more technical aspects :

"Synthesis of estradiol esters from estrone"
http://www.springerlink.com/content/j822347754071044/

Since this is not stereoselective (as far as I know), you'll have to separate the 13R from the 13S. The below diagram should help :

As for the mechanism, it is no different than any other reduction using

Code: Select all

NaBH4

.

lizneth07 · Post by **lizneth07** » Sun Jun 01, 2008 1:24 pm

Thank you Zedekiah for your help I did figure out the starting reactants and the product... what I'm not sure about is what exactly is meant by clearly explain the stereochemical route and comment on stereospecificity...

I really appreciate it..

Zedekiah · Post by **Zedekiah** » Sun Jun 01, 2008 2:18 pm

The hydroxyl group on the right of the estradiol can be pointed away from the screen (bottom of my picture) or away (top of my picture).

What this means is that the sodium borohydride can attack from the 'top'(when we're looking down at the page) or 'bottom' (if something was coming out of your monitor). I believe this reaction will provide a racemic mix of isomers.

If that doesn't answer it, I don't think I know what it means either.

lizneth07 · Post by **lizneth07** » Sun Jun 01, 2008 3:18 pm

Zedekiah, to me your answer sounds excellent. Thank you soo much.. I'm sure how much information is necessary but at least I have something to write down..

You're great!!