E2 Brutus? Part I

This is an experiment that I performed as part of a Chemistry Collaborations Workshops & Community of Scholars (cCWCS) workshop during the summer of 2011. I had planned on incorporating the experiment the next time I taught Organic Chemistry I. Since substitution and elimination is a topic in first semester organic chemistry (Chapter 6 in the Wade textbook), this lab is likely to be part of the students’ adventure in learning new laboratory techniques. For this reason, it is important to keep it simple because it is likely that they are doing some of these techniques for the first time. I wanted to use three different bases with a common substrate.

Reagents – bases:

I did a search of alkoxide bases in Sigma-Aldrich. Methoxide and ethoxide are available a concentrated solutions at a pretty reasonable price. Interestingly, both sodium and potassium salts are available for many of the bases. Generally, sodium is less expensive. The hindered alcohol, t-butoxide, is available as a solid with both sodium and potassium cations for about the same price. I ended up ordering both.  Other alkoxy bases are available but the price goes up considerably. Sigma-Aldrich has isopropoxide and tert-pentoxide salts. Sodium and/or potassium hydroxide may also be an option. There seem to be several cation variations besides sodium and potassium for many of these alkoxy bases.

Reagents – substrate:

I’m not sure what is all available for substrates. The most straightforward was to stick with 2-bromoheptane from the orginal article in Modern Projects and Experiments in Organic Chemistry: Miniscale and Standard Taper Microscale. 2nd ed. Mohrig, Hammond, Schatz, & Morrill. I found other references that used 3-chloro-3-methylpentane (Microscale & Miniscale Organic Chemistry Laboratory Experiments. Schoffstall, Allen; Gaddis, Barbara; Druelinger, Melvin) and 2-bromo-2-methylbutane (Experimental Organic Chemistry: A Miniscale and Microscale Approach. By John C. Gilbert, Stephen F. Martin).

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