Question

2,3-difluoro-1-methylcycloheptane or 1,2-difluoro-3-methylcycloheptane?

Couldn't 2,3-difluoro-1-methylcycloheptane also be called 1,2-difluoro-3-methylcycloheptane because there is more then one substitution group so could I not start counting from F instead of CH3?

Answer 1

You not only can, you must start counting from `"F"`.

Explanation:

The structure of the compound is

When you get the same numbers when counting in either direction, you use alphabetical priority in the naming.

Since `bbcolor(blue)("f")`luoro comes before `bbcolor(blue)("m")`ethyl, the correct name is 1,2-difluoro-3-methylcycloheptane.