Alkanes

Organic Chemistry IUPAC Nomenclature Demystified With A Simple Puzzle Piece Approach

Organic Chemistry IUPAC Nomenclature Demystified With A Simple Puzzle Piece ApproachOctober 21, 2014

IUPAC Nomenclature Demystified with a Simple Puzzle-Piece Approach, by Leah Fisch Note from James: This is a guest post by Leah Fisch of Leah4Sci.com , an online resource for learning organic chemistry, MCAT preparat…

Bridged Bicyclic Rings (And How To Name Them)

Bridged Bicyclic Rings (And How To Name Them)August 14, 2014

In the last post we started our discussion of structures with more than one ring, using decalin as our key example. We saw how much the stereochemistry at the ring junction can affect the overall shape of the molecul…

Which Cyclohexane Chair Is Of Lower Energy?

Which Cyclohexane Chair Is Of Lower Energy?July 23, 2014

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…

Substituted Cyclohexanes: “A Values”

Substituted Cyclohexanes:  “A Values”July 1, 2014

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, sinc…

The Cyclohexane Chair Flip

The Cyclohexane Chair FlipMay 30, 2014

In our last post, an aerial tour of the cyclohexane chair, we showed that there are two different positions a substituting can occupy on a cyclohexane chair – axial (straight up and down, relative to the ring) a…

An Aerial Tour Of The Cyclohexane Chair

An Aerial Tour Of The Cyclohexane ChairMay 14, 2014

  When I first learned about the cyclohexane chair (as we did in the last post) I was in denial about its importance in organic chemistry. From an aesthetic standpoint, it bothered me that cyclohexane wasn’…

Ring Strain in Cyclopentane and Cyclohexane

Ring Strain in Cyclopentane and CyclohexaneApril 18, 2014

In the last post, we saw that ring strain of cyclopropane and cyclobutane were 27 and 26 kcal/mol respectively.  They are the unhappiest of rings – constrained into uncomfortable angles, with hydrogens forced b…

Cycloalkanes – Ring Strain In Cyclopropane And Cyclobutane

Cycloalkanes – Ring Strain In Cyclopropane And CyclobutaneApril 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 vario…

Cycloalkanes – How To Calculate Ring Strain

Cycloalkanes – How To Calculate Ring StrainMarch 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 ri…

Cycloalkanes – Dashes And Wedges

Cycloalkanes – Dashes And WedgesMarch 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 …