Description: robs
Total Problems: 14
For the molecule shown below, indicate the hybridization (sp3, sp2, sp, etc.) of atoms A through H, and the bond angles of X, Y, and Z.
On the molecule below, mark each stereocenter with an asterisk. (Note: in some textbooks, stereocenters are referred to as stereogenic centers, chirality centers, or asymmetric centers).
Assign R or S configuration for each molecule below.
a) is straightforward. I've started you off in b).
Draw the structure of (2R,3S) 2-bromo-3-chlorobutane using wedges and dashes. Also draw a Fischer projection.
Indicate which of the molecules below are chiral (if any).
For a molecule to undergo an E2 reaction, the leaving group and the beta-proton must be in an anti-coplanar conformation (one atom straight up, the other straight down). Based on this, which compound undergoes E2 reaction with KOtBu faster? Why?
Indicate the major organic product of the reaction below. Include stereochemistry.
Let's work through a chiral resolution. Write out the structure of the indicated compound in each box. Include stereochemistry.
Why is it possible to separate the (R,R) and (R,S) salts?
After a sample of optically pure (S)-2-ethyl-cyclohexanone is dissolved in an aqueous solution for several hours, a significant loss of optical activity is observed. Explain.
Draw all possible resonance forms for each structure below. Use curved arrows.
Note that some structures only show charge, and not implied protons or lone pairs!
Let's perform conformational analysis on 2-methylbutane along the C2-C3 bond. We'll use the energy chart given below.
First, draw out the Newman projections along the C2-C3 bond, rotating the front carbon (C-2) by 60 degrees clockwise each time while keeping the back carbon (C-3) stationary.
According to the table above, how much energy does each conformation "cost?"
Second, make a plot of the total energy value for each Newman projection versus its dihedral angle.
α-D-Glucose is shown below. Draw its two chair forms. Which conformation is more stable? Explain.
I recommend using the common convention wedge = "up" and dash = "down."