Thermodynamic and Kinetic Control

February 9, 2012

First, an explanation. This happened. So things at MOC have basically  been on hold for a few weeks. Life is now returning to normal. The following discussion has nothing to do with the above, other than the fact that my dad’s best friend wryly observed of him: “When he opened his wallet, moths flew out”. [...]

Tagged as: 1, 2-addition, 4-addition, alkene stability, dienes, kinetic control, reaction coordinates, thermodynamic control, transition states, weird analogies

Read the full article →
Reaction Friday will return…

Reaction Friday will return…

February 3, 2012

… as will regular posting – next week. Organic chemist Brian Coppola of the University of Michigan recently won a $275,000 teaching award from Baylor University. The press release and his presentation are in the link below. Chemist Brian P. Coppola Wins Prestigious Teaching Award (University of Michigan) The hour-long talk is extremely good. Coppola [...]

Tagged as: off topic, teaching, videos

Read the full article →
Reaction Friday: Addition of HBr to alkenes

Reaction Friday: Addition of HBr to alkenes

January 21, 2012

The addition of HBr to alkenes is the focus of today’s video. Fast forward to the fifteen seconds at the end for maximum awkwardness. I am an idiot when it comes to this stuff. Is making videos supposed to be brutally fricking hard? I don’t know how Gary Vaynerchuk and Salman Khan do it. Thanks for [...]

Tagged as: alkenes, alkyl halides, hbr, markovnikoff, mechanismss, Reaction Friday, regiochemistry, videos

Read the full article →
Take “Don’t Memorize!” with a grain of salt

Take “Don’t Memorize!” with a grain of salt

January 19, 2012

Loyal reader Sandy writes in with a comment about memorization: I wish I had understood much earlier that there is a place for memorization in Orgo – like the reagents and what they contribute to a relationship, what reactions they are used with, etc. We were heavily discouraged not to memorize for the class – [...]

Tagged as: how to study, how to think, learning, memorization, mistakes

Read the full article →
How to apply electronegativity and resonance to understand reactivity

How to apply electronegativity and resonance to understand reactivity

January 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 structures? So what? Here’s the point: we can apply resonance (and electronegativity) to figure out the electron [...]

Tagged as: charges, electronegativity, formal charge, opposite charges attract, resonance

Read the full article →
Reaction Friday: Free-radical chlorination of alkanes

Reaction Friday: Free-radical chlorination of alkanes

January 13, 2012

One of the new things I wanted to do this year was to start doing videos. Since I was starting to run out of reagents to talk about for Reagent Friday, one thought was to start talking about reactions instead – and maybe make a video for each. So today starts a new experiment: Reaction [...]

Tagged as: alkanes, chlorination, Cl2, free radicals, halogenation, Reaction Friday

Read the full article →

Visual Guide to NMR Spectroscopy

January 11, 2012

Belated to get to this, but Jon Chui has made another beautiful graphic. You might recall his Pictorial Guide to Interpreting IR Spectra from awhile back. Now he’s made a visual guide to Interpreting 1H NMR Spectra, and it’s lovely. NMR is more information-rich than IR, so the task of putting *everything* on one reasonably [...]

Tagged as: IR, NMR, resources, spectroscopy, visual aids

Read the full article →

Common Mistakes: How not to draw resonance curved arrows

January 10, 2012

No discussion of resonance structures would be complete without mention of how to royally screw them up. This isn’t something to feel bad about, by the way: there isn’t a chemist alive who hasn’t made one of these mistakes at some point. Think of it as a rite of passage. The trick is to make the mistakes [...]

Tagged as: accounting, curved arrows, electrons, mistakes, resonance

Read the full article →

(Belated) Thanks for a great 2011… How Can M.O.C. Help you in 2012?

January 6, 2012

Sorry it’s taken so long to get back in the swing of things. I’ve just returned from some time Up North. What do a bunch of Canadians do when it’s –15°C outside in late December? They invite their family and friends over for a pond curling tournament! This was the cap to a great 2011. [...]

Read the full article →

In Summary: Resonance

December 22, 2011

After all these posts about resonance, I thought it would be good to have a post summarizing what’s been discussed so far. One of the key skills in analyzing the reactivity of a molecule is to be able to figure out where the electrons are.  As I wrote here, if we’re dealing with single bonds, [...]

Tagged as: arrow pushing, charge stabilization, electron density, least charges, negative charge, pi acceptors, pi donation, positive charge, resonance

Read the full article →