In the face of mounting evidence revealing active learning approaches result in improved student learning outcomes compared to traditional passive lecturing, there is a growing need to change the way instructors teach large introductory science courses. However, a large proportion of STEM faculty continues to use traditional instructor-centered lectures in their classrooms. In an effort to create a low barrier approach for the implementation of active learning pedagogies in introductory science courses, flipped classroom modules for large enrollment general chemistry course sequence have been created. Herein is described how student response systems (clickers) and problem-based case studies have been used to increase student engagement, and how flipped classroom modules have integrated these case studies as collaborative group problem solving activities in 250-500 seat lecture halls. Preliminary evaluation efforts found the flipped classroom modules provided convenient access to learning materials that increased the use of active learning in lecture and resulted in a significant improvement in the course grade point average (GPA) compared to a non-flipped class. These results suggest this approach to implementing a flipped classroom can act as a model for integrating active learning into large enrollment introductory chemistry courses that yields successful outcomes.