inspired by @Timo I found the following solution to work for me.
import subprocess
outlookpath2doc = '"C:/Program Files (x86)\Microsoft Office\Office14\OUTLOOK.EXE"'
compose = '/c ipm.note'
recipients = '/m "recipient@example.com; recipient2@example.com&subject=Please take a look at this"'
attachment = '/a "' + path2doc + '"'
command = ' '.join([outlookpath2doc, compose, recipients, attachment])
process = subprocess.Popen(command, shell=False, stdout=subprocess.PIPE)