Answer
1 - O
2 - (Left) Carbon
3 - (Right) Carbon
4 - H
Work Step by Step
1. Make a list with all atoms connected to the stereocenter, and rank them by atomic number.
- H, O, C, C.
By atomic number:
- O, C, C, H
2. As we can see, there are 2 equal atoms, so we will have to find which one has the priority.
- We can do that by analyzing the atoms connected to them:
- To the left carbon: O, C, C.
- To the right carbon: C, C, C.
** Since there is an oxygen on the left carbon, it will get priority.
3. Now, put the numbers in order:
1 - O
2 - (Left) Carbon
3 - (Right) Carbon
4 - H