Drawing Reaction Mechanisms

An Arrow-Pushing Dilemma In Concerted Reactions

An Arrow-Pushing Dilemma In Concerted ReactionsApril 5, 2013

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 …

Rearrangements in Alkene Addition Reactions

Rearrangements in Alkene Addition ReactionsFebruary 26, 2013

In exploring reactions that proceed along the carbocation pathway, every once in awhile you might see an example of an addition reaction that looks a little… strange. The alkene is gone, two new bonds have formed, b…

Comparing the E1 and E2 Reactions

Comparing the E1 and E2 ReactionsOctober 10, 2012

Now that we’ve gone through the mechanisms of the E1 and E2 reactions, let’s take a moment to look at them side by side and compare them. Here’s how each of them work: Here’s what each of these…

The SN2 Mechanism

The SN2 MechanismJuly 4, 2012

Having gone through the two different types of substitution reactions, and talked about nucleophiles and electrophiles, we’re finally in a position to reveal the mechanism for one of the most important reactions…

Acid Base Reactions Are Fast

Acid Base Reactions Are FastMay 21, 2012

Common dilemma in organic chemistry as you move through the latter parts of Org 1 and then into Org 2: When more than one reaction is possible, how do you know which one will happen? In a steel cage match between an a…

Curved Arrows (2): Initial Tails and Final Heads

Curved Arrows (2): Initial Tails and Final HeadsFebruary 29, 2012

Here’s a handy little trick for accounting for charges when you draw curved arrows. You know by now that curved arrows are our accounting system for showing how electrons move, from the tail (electron donor, sou…

The Third Most Important Question to Ask When Learning A New Reaction

The Third Most Important Question to Ask When Learning A New ReactionFebruary 20, 2012

When learning any new reaction, I think you always have to start with the “what”. What bonds are forming, and what bonds are breaking. After you answer “what”, then you can start asking “…

Curved Arrows (for reactions)

Curved Arrows (for reactions)February 15, 2012

If you think of electrons as the currency of chemistry, reactions are transactions of electrons between atoms. Just like double entry book keeping was developed to formalize how financial transactions  are recorded, …

How to apply electronegativity and resonance to understand reactivity

How to apply electronegativity and resonance to understand reactivityJanuary 17, 2012

One thing has been missing from the discussion of resonance. What’s the point? Who cares if we can write out resonance structures? What does it matter if we can figure out the two or three most stable resonance …

Grossman’s Rule

Grossman’s RuleOctober 6, 2011

A few months ago after putting up this post on “Hidden Hydrogens, Hidden Lone Pairs, and Hidden Counterions”, commenter Stewie Griffin made me aware of this little gem:  With regards to hidden hydrogens, …