Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: azmanam on July 20, 2009, 07:13:55 AM
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QUESTION: Explain the stereochemical results for the following transformation
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Initially SN2 displacement of mesylate by iodide, then SN2 displacement of that iodide by iodide (eventually) racemises the system?
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Yup. Two quick ones in a row... I guess I'll have to start making them harder :)
Iodide is a great nucleophile and a great leaving group. Initial formation of the optically pure iodide is soon attacked by the good nucleophile I- to liberate the good leaving group I- to give the iodide with the opposite configuration. Repeated attack of I- to liberate I- eventually provides the racemate. No SN1 mechanism is proposed.
I've updated the LAH reduction with a different focus. Take a look at that if you want another challenge this week. http://www.chemicalforums.com/index.php?topic=33985.0