Answer
1 - O
2 - C (Top right)
3 - C (Bottom left)
4 - H
Work Step by Step
1. Identify the stereocenter.
2. List all atoms connected to the stereocenter, and rank them by the atomic number.
- O, H, C, C
Ranked by atomic number:
- O, C, C, H
3. As we can see, there are 2 equal atoms, there are two methods for finding their order.
First Method (Faster):
- Find the closest variation in the chain (Double bond, Substituent).
- The chain with the closer variation gets priority.
In this case:
- Top right chain: Methyl on the first carbon.
- Bottom left chain: Oxygen on the third carbon.
- Therefore, the top right chain gets priority.
Second Method:
- Compare the atoms connected to each carbon, and if you don't get the answer, them look at the atoms connected to them.
In this case:
Top right carbon: C, C, H
Bottom left carbon: C, H, H
- Since (C>H), the top right carbon gets priority,
4. Put the numbers on the stereocenter atoms:
1 - O
2 - C (Top right)
3 - C (Bottom left)
4 - H
