Chem 242 @ Dickinson

Ethers, an Introduction

Today we started Chapter 18 and the focus was on how to make ethers and what one can do with them after they are synthesized. Two main synthetic methods for ethers discussed were the Williamson ether synthesis and alkoxymercuration. For the Williamson, the key is the manufacture of the alkoxide followed the addition of an alkyl halide which can undergo an SN2 reaction with the alkoxide. The alkoxymercuration was shown to be an analogy to the hydroxymercuration that we covered in Chem 241.

There were two main reactions of ethers. First was the cleavage with HI -- this was the tricky one, as it required the determination of whether or not a tertiary carbon was attached to the oxygen before determining the ultimate fate of the ether. Basically: no tertiary carbon, the iodide attacks the less hindered carbon; with a tertiary carbon the protonated ether fragments to create a tertiary carbocation. We also discussed the Claisen rearrangement, and drew parallels to the Diels-Alder reaction.

I have corrected the second part of ps #2's key (with some loss of resolution) and have posted ps 3 and its key. The to-do list for next week is also up.

posted by DCChem @ 10:03 AM