dplyr:: How to use SE and `%in%` in `filter`?

Consider

df = data.frame(col1 = 1:3, col2 = 2:4)

I want to do

df %>%
  filter(col1 %in% 2:3)

which should return the 2nd and 3rd row, but col1 is passed in as a string as variable str_1 = "col1"

So I tried

  str_1 = "col1"
  df %>% 
    filter(!!!str_1 %in% 2:3)

  df %>% 
    filter(!!str_1 %in% 2:3)

and niether worked. What's the right syntax for this? And what's an easier way to remember these dplyr tricks?