Just use bounding quotes for the full path of .whl file.
pip install "C:\...full path with spaces\pywin32-...-win_amd64 (1).whl"
Of course make sure pip install wheels
was run first.
Alternative way is using easy_install (not necessary to download the installer manually):
easy_install.exe https://github.com/jmdaweb/TWBlue_deps_windows/raw/master/x64/pywin32-220.win-amd64-py2.7.exe
But the second way may cause problems with py2exe if you have plans to use it. Maybe pip install pypiwin32
is OK for you (it will install pyWin32 build 219, should work just fine for most cases).