Answer
For the first chair:
- (Br) on the carbon number 1, on the "up" side.
- (Me) on the carbon number 4, on the "up" side.
For the second chair, just move the substituents by 1 carbon, and use the skeleton for the second chair. (Page 124)
Work Step by Step
For the first chair:
1. Start by numbering the carbons on the hexagon structure:
For the drawing below, we started counting from the top carbon, and in clockwise direction.
** You can choose any carbon and any clock direction, but you will have to follow the same rules for the chair drawing.
2. Identify the substituents, their positions, and if they are in a wedge or a dash:
- Bromo, Carbon 1, Wedge.
- Methyl, Carbon 4, Wedge.
3. Draw the chair structure, and put the numbers on it:
- You can choose any carbon as first one, but we will have to use the same clock direction that we used in the first structure.
- In this drawing, we will start from the top right carbon, and we will use the clockwise direction.
4. Place the substituent in the chair structure:
- Follow the pattern in page 117 and you should be fine.
- (Br) on the carbon number 1, on the "up" side.
- (Me) on the carbon number 4, on the "up" side.
** Wedge groups are put in "up", and dash groups, in "down".
** Optionally, you can draw the hydrogens missing in the carbons with substituents.
For the second chair, follow the same steps, but you will have to move all the substituents by one carbon, and draw them on the "skeleton" of a flipped chair (Page 124).
In this case, we will still be counting the numbers in clockwise direction, but the number 1 carbon will be the one at the bottom right.
