Master Organic Chemistry

Classification of Isomers: Constitutional Isomers, Stereoisomers, Enantiomers, and Diastereomers

September 10, 2018 By James Ashenhurst 2 Comments

"How Are We Related, Again?"  A few weeks ago, at a family reunion in Ontario,  I introduced my relatives to the joy of liquid nitrogen ice cream. My cousins were there, as were many of their children. So were a few of my dads' cousins. Being a family reunion,  they invited their (grown) children, … [Read more...]

Filed Under: Organic Chemistry 1, Stereochemistry Tagged With: atropisomers, conformations, constitutional isomers, diastereomers, enantiomers, Lord Voldemort, meso, stereoisomers, tartaric acid

s-cis and s-trans

May 12, 2017 By James Ashenhurst 1 Comment

s-cis and s-trans. What does those terms mean? Recall cis and trans. The reason Aldrich Chemical Co. can sell 99% cis-2-butene and 99% trans-2-butene in separate bottles is because of restricted rotation about the C-C pi bond. Rotation would destroy the overlap of the adjacent p-orbitals, and … [Read more...]

Filed Under: Conformations, Dienes and MO Theory Tagged With: conformations, dienes, s-cis, s-trans

Assigning R/S To Newman Projections (And Converting Newman To Line Diagrams)

February 1, 2017 By James Ashenhurst 2 Comments

This post was co-authored with Matt Pierce of Organic Chemistry Solutions.  Ask Matt about scheduling an online tutoring session here. In two recent posts we discussed how to assign (R/S) to configurations of chiral carbons in a variety of situations, both simple and more complex. So far, all … [Read more...]

Filed Under: Conformations, Stereochemistry Tagged With: bond-line, cahn-ingold-prelog, cats, chirality, conformations, eclipsed, newman projection, staggered

How To Do Bond Rotations

July 6, 2012 By James Ashenhurst 1 Comment

Bond rotation can be a tricky skill for first timers, and it's a subject that doesn't really lend itself to a text-laden blog post. You just have to "see it in action". This video walks through it using the "steering wheel" analogy. Hope it's useful to students out there who are having difficulty … [Read more...]

Filed Under: Conformations, Stereochemistry Tagged With: bond rotations, conformations, stereochemistry, stereoisomers, video

The Ups and Downs of Cyclohexanes

March 16, 2011 By James Ashenhurst 3 Comments

Drawing cyclohexane chair forms can be a tricky business. While it's often intuitive to pick out which groups are up and down when they're axial (i.e. pointing straight up or down), it's tougher for beginners to see that equatorial groups (the ones pointing "somewhat up" or "somewhat down") can be … [Read more...]

Filed Under: Alkanes, Conformations, Organic Chem Study Tips, Organic Chemistry 1 Tagged With: boats, chair flips, chairs, conformations, cyclohexanes, dashes, drawing, steric hindrance, wedges

On Cats, Part 3: Newman Projections

November 22, 2010 By James Ashenhurst 18 Comments

Do you know where the saying "there's more than one way to skin a cat" comes from? Me neither. But I do know one thing: there is more than one way to draw cat conformations. Last time I introduced the Cat Line Diagram and showed how we can use it to depict these 3-dimensional creatures on a … [Read more...]

Filed Under: Conformations, Organic Chemistry 1, Stereochemistry Tagged With: cats, conformations, eclipsed, newman proejctions, rotation, staggered, stereocenters

On Cats, Part 1: Conformations and Configurations

November 11, 2010 By James Ashenhurst 34 Comments

[NOTE: this has been amended to correct some confusion on my part on the difference between configurational and constitutional isocats. Thanks to Prof. Gary Weisman (UNH) for making me aware of the error] As I said earlier, I've given up writing about organic chemistry. If you're expecting to … [Read more...]

Filed Under: Conformations, Organic Chemistry 1 Tagged With: cats, configurational, configurations, conformations, constitutional, fun, isomers

The Many, Many Ways of Drawing Butane

October 15, 2010 By James Ashenhurst 3 Comments

One of the skills you have to develop early in Org 1 is to learn the different conventions for drawing molecules. Let's use butane as an example. Butane is pretty boring molecule, frankly. It's four carbons in a row. Not much more to it than that. However, even a simple molecule like butane … [Read more...]

Filed Under: Alkanes, Chemical Bonds, Conformations, Nomenclature, Organic Chemistry 1 Tagged With: abbreviations, alkanes, bond rotations, conformations, dashes, drawing, hidden hydrogens, newman projections, nomenclature, wedges

Copyright © 2019 · MasterOrganicChemistry.com · All Rights Reserved
Organic Chemistry Is Awesome