TriStar Pictures has boosted veteran development executive Michael Besman to the post of executive veepee of production, just days before the release of its summer comedy “Sleepless in Seattle,” it was confirmed Monday.Besman joined TriStar 16 months ago, following a six-year run at Guber Peters Entertainment Co. and three years at Paramount Pictures under the tutelage of former studio executive and current Walt Disney Studios chairman Jeffrey Katzenberg. One of the first pictures Besman was involved with at TriStar was the Tom Hanks/Meg Ryan starrer “Sleepless,” whose release was bumped by TriStar from March 26 to Friday after several positive test screenings (Daily Variety, Jan. 19). Besman’s promotion was announced by TriStar president of production Stacey Lassally. At the studio, Besman works closely with such producers as Ned and Nancy Graham Tanen, Laura Ziskin and Allyn Stewart. Currently, Besman is involved in the development of director Kenneth Branagh’s adaptation of “Mary Shelley’s Frankenstein,” which is set to star Robert De Niro and Branagh. The fall production is based on a screenplay by Steph Lady and Frank Darabont.