Which direction are you going? Are you copying from OS X to the RPi or vice versa?
I presume you mean SFTP and not FTP. If you really have been trying old, deprecated FTP, please try switching to SFTP. That should give you the exact same system permissions as you have normally.
Also, OSX and GNU/Linux use forward slashes / and not back slashes \ for directory hierarchies. The backslash won't work in that context because it means to take the character immediately following the backslash \ to be interpreted literally.