Newman Projections of Butane Let’s start today’s discussion with the definition of a conformation. The different spatial arrangements of the atoms that result from rotation about a single bond are called conformers or conformational isomers.To illustrate the conformations of butane, we need to … Read more
In the previous post, we talked about the staggered and eclipsed conformations of ethane, and saw that these are the least and most stable conformations that differ by a 12 kJ/mol rotation barrier: The staggered conformation is the … Read more
From General Chemistry and earlier chapters of Organic Chemistry, we know that C-C single bonds are formed by a linear overlap of sp3 orbitals. As an example, let’s recall how each carbon in ethane provides one sp3 orbital to form … Read more
To determine the R and S configuration of a chiral carbon in Newman projections, we need to look through the bond such that the lowest priority group is pointing back. But first, one question – why would anyone need to … Read more
In this post, we will learn how to convert between Fischer, Bond-line, and Newman projections in different orders. This is an essential skill as it helps to visualize the molecule in space, and that is what a significant part of … Read more
Torsional and Steric Strain In the previous post, we talked about the Newman projections where we also covered the relative energies of anti, gauche, and syn conformations. The destabilization of certain conformations is due to Steric or Torsional strain. These two … Read more
What is the R and S Configuration, and why do we need it? If we name these two alkyl halides based on the IUPAC nomenclature rules, we get the name as 2-chlorobutane for both: … Read more
In this post, we will talk about the stereochemistry of radical halogenation leading to racemic mixture of enantiomers or diastereomers. Before getting into more details, let’s recall that radicals are similar to carbocations as both are trigonal planar, sp2-hybrydized atoms … Read more
Consider these E2 elimination reactions. For both, the β hydrogens are on the right side of the Br, and as expected, that’s where the double bond appears in the product: So, no problems with the regiochemistry of these … Read more
What are the Fischer Projections? Fischer projections are just another way of drawing compounds containing chiral centers. They were initially proposed by Emil Fischer for making it easier to draw the structures of compounds containing multiple chiral centers, with the … Read more
