Monitor Group, a Cambridge consulting firm founded by Harvard Business School professor Michael E. Porter that rose to prominence in the 1980s, filed for bankruptcy protection Wednesday as part of a deal to be acquired by Deloitte Consulting.

Monitor was involved in a controversy last year over the revelation it was paid $3 million a year from 2006 to 2008 to help improve the image of now-deceased Libyan dictator Moammar Khadafy. The firm apologized for the arrangement in 2011, calling it a “major mistake.”