Questions: Answer the following questions about the molecule shown below. a) Using proper naming nomenclature, number the carbon atoms in the ring with numbers 1-6 (starting with 1 on the carbon the chlorine is attached to). Then provide the complete name for the molecule. b) Fill in the substituents for the two possible chair conformations for this molecule. The substituent numbers from the structure above should match the substituent numbers on the chair structures below. Pay close attention to whether a substituent is axial or equatorial.

Answer the following questions about the molecule shown below.
a) Using proper naming nomenclature, number the carbon atoms in the ring with numbers 1-6 (starting with 1 on the carbon the chlorine is attached to). Then provide the complete name for the molecule.
b) Fill in the substituents for the two possible chair conformations for this molecule. The substituent numbers from the structure above should match the substituent numbers on the chair structures below. Pay close attention to whether a substituent is axial or equatorial.

Transcript text: Answer the following questions about the molecule shown below. a) Using proper naming nomenclature, number the carbon atoms in the ring with numbers 1-6 (starting with 1 on the carbon the chlorine is attached to). Then provide the complete name for the molecule. b) Fill in the substituents for the two possible chair conformations for this molecule. The substituent numbers from the structure above should match the substituent numbers on the chair structures below. Pay close attention to whether a substituent is axial or equatorial.

Solution

Solution Steps

Step 1: Numbering the carbon atoms

The chlorine atom is the main functional group, so the carbon it's attached to gets numbered 1. The numbering continues around the ring, so the carbon with the methyl group is number 2.

Step 2: Naming the molecule

The parent chain is cyclohexane. There are two substituents: chlorine and methyl. Chlorine comes first alphabetically. Since the chlorine is on carbon 1 and the methyl is on carbon 2, the full IUPAC name is 1-chloro-2-methylcyclohexane.

Step 3: Filling the substituents in chair conformations

In the first chair conformation, carbon 1 (with Cl) is pointing down, so the Cl will be axial down. Carbon 2 (with CH3) is pointing up, so the CH3 will be equatorial up.

In the second chair conformation (after the ring flip), carbon 1 (with Cl) is pointing up, so the Cl will be axial up. Carbon 2 (with CH3) is pointing down, so CH3 will be equatorial down.

Final Answer:

a) 1-chloro-2-methylcyclohexane

b) See the image below:

[asy] // First chair pair A, B, C, D, E, F; A = (0,0); B = dir(60); C = B+dir(0); D = C+dir(-60); E = D+dir(180); F = E+dir(60);

draw(A--B--C--D--E--F--cycle); draw(A+(0,.4)--A); draw(B+(dir(120)_.4)--B); draw(C+(.4,0)--C); draw(D+(0,-.4)--D); draw(E+(-.4,0)--E); draw(F+(dir(240)_.4)--F);

label("Cl", A+(0,.5)); label("CH$_3$",C+(.5,0)); label("1", A, SW); label("2", C, E); label("3", D, SE); label("4", E, NE); label("5", F, NW); label("6", B, N);

// Arrow draw((2.5,0)--(3.5,0),Arrow);

// Second chair pair G, H, I, J, K, L; G = (4.5,0); H = G+dir(60); I = H+dir(0); J = I+dir(-60); K = J+dir(180); L = K+dir(60);

draw(G--H--I--J--K--L--cycle); draw(G+(0,-.4)--G); draw(H+(dir(240)_.4)--H); draw(I+(-.4,0)--I); draw(J+(0,.4)--J); draw(K+(.4,0)--K); draw(L+(dir(120)_.4)--L);

label("Cl", J+(0,.5)); label("CH$_3$",I+(-.5,0));

label("1", J, NE); label("2", I, W); label("3", H, NW); label("4", G, SW); label("5", K, SE); label("6", L, E);

[/asy]

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