Try doing split jumps. Get into the split position, then jump and switch forward and backward legs. Do this for 10 reps x 2-3 sets as warm-up for the jerk.
Also, after your jerk and/or C&J work, you can do split recoveries. Load up a bar in a squat rack on safety pins with the bar at top of forehead. Load the bar up, then stand under the bar with hands in jerk grip, get on toes, then quickly punch into the split jerk. The bar will not come off the pins when you do this, until you recover from the split position.
Another exercise you can do is jerk split under. As warm-ups for CJ or jerks, take the empty bar on your shoulders in jerk position. Get on toes and with NO hip extension, "pop"/punch under the bar into the split position, stay there for a second or two to re-inforce that position, then recover.
Hope these help!!