Typescript: Is there a way to extend an interface, but modify property names?

Question

Have a look at this simple interface:

inteface Foo {
  bar: any
}

I want to create this interface from the above one:

inteface Foo2 {
  bar$: any
}

in other words, I want to append $ to every property of Foo Interface.

Of course something like this didn't work:

type Foo2 = {
    [(K in keyof Foo) + '$']: Observable<Foo[K]>
}