New York-based O'Connor Group, a real estate development and investment firm that principally invests through private equity funds, announced the formation of Elysian Watertown Square Residential Property Owner, LLC, a joint venture consisting of the O'Connor Group, Denver-based private equity firm FrontRange Capital Partners and Japan's Takenaka Corp. and started construction on a 142-unit residential and retail complex at 53 Pleasant St. in Watertown, Massachusetts.