Organic Chemistry 1

Cycloalkanes – Ring Strain In Cyclopropane And Cyclobutane

April 3, 2014

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 went above 12. Based on these [...]

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Cycloalkanes – How To Calculate Ring Strain

March 24, 2014

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 out you can learn [...]

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Cycloalkanes – Dashes And Wedges

Cycloalkanes – Dashes And Wedges

March 20, 2014

In the last post, we mentioned that one of the consequences of the fact that carbon can form rings is that small rings (less than 8 carbons) are so rigid that they can’t be turned inside out [video]. One of the important consequences of this, as we’ll see today, is that it leads to the [...]

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Crash Course On Resonance

Crash Course On Resonance

March 13, 2014

One extremely common type of email I get from students goes like this: “I feel way behind on [X] and my exam is coming up in a few days. Do you have any advice?”  Privately, I think: “Sure – do a series of good practice problems on [X], and you’ll be very well prepared.”  But that [...]

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Synthesis (5) – Reactions of Alkynes

Synthesis (5) – Reactions of Alkynes

January 29, 2014

Today, we’re going to add the reactions of alkynes to our reaction map, which will bring to a close all the major reactions we’ve discussed so far in a typical first semester course. Like alkenes, the main pathway found in the reactions of alkynes is “addition” – that is, breaking the C-C π bond and forming [...]

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Synthesis (4) – Reactions of Alkenes

Synthesis (4) – Reactions of Alkenes

January 21, 2014

In the last post on alkenes we covered the reactions of alkyl halides and it made out tiny little reaction map explode into a cascade.  Here we’re really going to blow up our reaction map, because we’re going to talk about a second very important “hub” for synthesis – alkenes. If you haven’t already noticed…. there [...]

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Success Stories: How Zach Aced Organic Chemistry 1

Success Stories: How Zach Aced Organic Chemistry 1

January 16, 2014

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 university [...]

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Synthesis (3) – Reactions of Alkyl Halides

Synthesis (3) – Reactions of Alkyl Halides

January 10, 2014

In the last post, we began our discussion of synthesis by starting with the reactions of alkanes. Since we’ve learned only one important class of alkane reactions so far (free-radical halogenation), our “reaction map” was very small.  Today we will visit the reactions of a much more synthetically versatile functional group: alkyl halides. Using our [...]

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Synthesis (2) – Reactions of Alkanes

Synthesis (2) – Reactions of Alkanes

December 19, 2013

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 H2O from organic starting materials is not very useful from a synthetic [...]

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Introduction To Synthesis

Introduction To Synthesis

December 17, 2013

By this point we’ve gone over all the major classes of reaction covered in many typical first semester organic chemistry courses.: acid base, substitution, elimination, addition, free-radical reactions, even oxidative cleavage.  Our primary focus has been looking at these reactions as means of transforming one functional group into another, which is the most intuitive way [...]

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