NEW YORK CITY — Sentinel Real Estate Corp. has completed the disposition of a five-building multifamily property, known as the Fort Riverside portfolio, in Manhattan. A group of real estate investors led by Joshua Sternhell and David Katz acquired the portfolio sold for $101.5 million, or $300 per square foot. The 341,148-square-foot portfolio features 289 apartments along Fort Washington Avenue and Riverside Drive at 66-72, 80 and 86 Fort Washington Ave. and 838 and 884 Riverside Drive. Additionally, the assets include a combined 199,000 square feet of air rights. Lazer Sternhell and Peter Vanderpool of Cignature Realty Associates represented the buyers, while Robert Shapiro, Bob Knakal and Jonathan Hageman of Cushman & Wakefield represented the seller in the deal.