Redirecting folder and contents separately

Hi,

I am changing my url structure.

I have redirected http://domain/folder/files to http://domain/files without a problem, using;
source: ^/folder/(.*)$
target: /$1

I also need to redirect http://domain/folder to http://domain/otherfolder
I added this redirection but it did not work;
source: ^/folder/?$
target: http://domain/otherfolder

How can I achieve this second redirection?

Thanks

https://wordpress.org/plugins/redirection/