A few months ago my mom came down to visit, and we had a fun lunch at my favourite aquarium restaurant. On our drive home, we got on the highway in the rain and turned a corner only to be confronted with a sea of red brake lights. Stomping on the brake, I barely managed to stop in time. However, … [Read more...]
Our New Book, “Practice Organic Mechanisms”, Is Out
Today I'm delighted to announce a new book - Practice Organic Mechanisms, co-written with Dr. Michelle Sulikowski, Senior Lecturer of Organic Chemistry at Vanderbilt University. Practice Organic Mechanisms is a 168-page, spiral-bound, physical book that provides guided mechanism practice for … [Read more...]
Synthesis (6) – Reactions of Alcohols
The Alcohol Reaction Map Having now finished (at long last) covering the key reactions of alcohols, let's stop to put everything in perspective. Over the past 18 articles (!) in this series on alcohols, we covered reactions such as: Ether formation via substitution reactions Elimination … [Read more...]
How Concepts Build Up In Org 1 (“The Pyramid”)
I LOVE making maps. Whenever I played adventure games as a kid (or, let’s face it, as an adult) I often made meticulous maps of how each area led to the next. Any time I really want to understand something, I have to write everything out and make a map to connect things together - usually after I’ve … [Read more...]
Which Cyclohexane Chair Is Of Lower Energy?
In the last post, we introduced A values and said they were a useful tool for determining which groups are "bulkiest" on a cyclohexane ring. The greater the A-value (bulk), the more favoured the equatorial conformer will be (versus axial). We saw that hydroxyl groups (OH) have a relatively low … [Read more...]
Substituted Cyclohexanes: “A Values”
In the last post we saw that adding a methyl group to cyclohexane results in two chair conformers that are unequal in energy. We saw that the conformer where the methyl group was equatorial is the most stable, since it avoids destabilizing diaxial interactions (technically, gauche interactions) that … [Read more...]
Cycloalkanes – Ring Strain In Cyclopropane And Cyclobutane
In the last post we saw that cyclopropane and cyclobutane have an unusually high “ring strain” of 27 kcal/mol and 26 kcal/mol respectively. We determined this by comparing heats of combustion from rings of various sizes, and saw that the ΔHcombustion per CH2 was essentially constant as ring sizes … [Read more...]
Cycloalkanes – How To Calculate Ring Strain
In the last post we learned about one consequence of the fact that carbon can form rings - that we can form stereoisomers (cis / trans). This post attempts to explain another very interesting consequence of ring formation. This whole post is about strain. It all starts with this: it turns … [Read more...]
Success Stories: How Zach Aced Organic Chemistry 1
With the first semester over, I recently asked my readers if they could share their stories of how they succeeded [or even failed in] organic chemistry. In the first of a series of posts, I'll share the response from Zach, who reports earning an A in organic chemistry 1 at a prestigious Ivy League … [Read more...]
Synthesis (2) – Reactions of Alkanes
In this post we're going to begin building our reaction map, starting with the simplest organic compounds of all: alkanes.*We've only learned one synthetically important class of alkane reaction: free-radical halogenation. [Combustion is also technically a reaction of alkanes, but producing CO2 and … [Read more...]