All things being equal, it is more important to have a firm contact with the shoulders than with the hands. Most lifters will not be able to completely wrap the bar and some coaches argue that closing the hand over the bar is not desired in the jerk starting position.
Try moving your elbows side to side to "walk" the hand under the bar, one side at a time. You are allowed to attempt the jerk "in your time", so no need to rush if you're not set.
You can also try shrugging hard to bounce the bar a bit so you can move your hands up. Just don't bend your knees or it might be seen as a jerk attempt.
Or you can learn to jerk from a fingertip position, which many lifters choose to do.