4. Alkanes and Cycloalkanes

Draw Newman projections of the following molecules viewed from the direction of the blue arrows.

(a)

Convert the following Newman projections to skeletal structures and name them.

a.

b.

Draw all the staggered and eclipsed conformers that result from rotation about the C-2-C-3 bond of pentane.

Using Newman projections, draw the most stable conformer for each of the following:

b. 3-methylhexane, viewed along the C-3----C-4 bond

Using Newman projections, draw the most stable conformer for each of the following:

a. 3-methylpentane, viewed along the C-2---C-3 bond

Draw a potential-energy diagram for rotation about the C-2---C-3 bond of pentane through 360°, starting with the least stable conformer.

For rotation about the C-3---C-4 bond of 2-methylhexane, do the following:

a. Draw the Newman projection of the most stable conformer.

b. Draw the Newman projection of the least stable conformer.

c. Draw Newman projections of the two conformers of the trans isomer.

d. Which of the conformers predominates at equilibrium?

Given the following structures, show the Newman projection that would result from looking down the indicated bond in the direction shown. [Orient yourself as if you were the eyeball looking down the bond. Some of the examples have been partially completed for you to fill in the rest.]

(k) <IMAGE>

Given the following structures, show the Newman projection that would result from looking down the indicated bond in the direction shown. [Orient yourself as if you were the eyeball looking down the bond. Some of the examples have been partially completed for you to fill in the rest.]

(j) <IMAGE>

Using the Newman projections shown, draw each molecule in its line-angle drawing with all hydrogens and substituents shown. [Carbon b is behind carbon a in these structures.] Wedges and dashes should be used to indicate whether a substituent is coming out of, or going into, the plane of the page.

(b)

Using the Newman projections shown, draw each molecule in its line-angle drawing with all hydrogens and substituents shown. [Carbon b is behind carbon a in these structures.] Wedges and dashes should be used to indicate whether a substituent is coming out of, or going into, the plane of the page.

(d)

Given the first Newman projection and the direction and degree of rotation, fill in the resulting Newman projection. [One substituent has been labeled for you.]

(a)

Given the first Newman projection and the direction and degree of rotation, fill in the resulting Newman projection. [One substituent has been labeled for you.]

(d)

Given the first Newman projection and the direction and degree of rotation, fill in the resulting Newman projection. [One substituent has been labeled for you.]

(h)