In the law firms Barack, Ferrazzano, Kirschbaum & Nagelberg LLP added Joshua W. Mahoney as an associate in its litigation group. Mahoney is a trial lawyer with experience representing clients in high-stakes disputes. He was previously with Grippo & Elden LLC. • Sidley, Austin LLP is representing pharmacy benefits manager Catamaran Inc. in its $405 million acquisition of Healthcare Solutions Inc. The lead lawyers on the transaction are Gary D. Gerstman, an M&A partner; Michael P. Heinz, a …