The carbon adjacent to an aromatic ring - the "benzylic" carbon - can participate in several useful and interesting reactions. Today we'll provide examples and mechanisms for two key examples: benzylic bromination and benzylic oxidation. Here's the quick summary: Alkyl Groups = Roughage In … [Read more...]
An Arrow-Pushing Dilemma In Concerted Reactions
Up to now, drawing out reaction mechanisms using the curved arrow formalism has been fairly straightforward. Yes, sometimes there is some ambiguity with respect to which carbon of a C-C π bond is forming a new bond to an electrophile, but that can be readily solved by adding a few … [Read more...]
Alkene Addition Pattern #2: The “Three-Membered Ring” Pathway
The "Three-Membered Ring" pathway In the last post we walked through a proposal for how the bromination of alkenes works and showed that it adequately explains many of the experimental observations made for this reaction. Namely, the reaction proceeds with anti addition of substituents across the … [Read more...]
Another awesome example of acid catalysis: Acids catalyze keto-enol tautomerism
Between posts on tautomerism and on lewis acid catalysis, I neglected to mention a really important point in carbonyl chemistry that illustrates another facet of acid catalysis: Acids catalyze keto-enol interconversion. What am I talking about? Let's back up for a second. Remember ketones and … [Read more...]