Who to contact in Corporate Finance?

Try the CFO.

In all seriousness you should try to reachout to recruiters or senior directors of finance at fortune 500 firms via Linkedin. It shows you have hustle assuming that you aren't socially awkward, they could place your resume in the hands of who it needs to be.

Although, the best route is knowing someone in the company.

I wouldn't go after senior directors to start. Maybe if you have some sort of connection to them. Aim for Financial Analysts to Manager level guys. Really the most help they will be is getting your res past HR (which should get you at least a phone interview). From there, it's up to you to do well in the interviews.

Let me guess... sophomore in high school?

maybe try your alumni with whom you can build a connection with. Cold-calling is always a bit hit or miss i find

Shoot for Manager/Sr. Manager/Director. Anyone lower than Manager typically won't have enough pull to get you an internship (or create an internship for you... this happens). Anyone higher likely won't have the time and may ignore a college student. Honestly, it probably depends more on the person than it does their title, so you just have to reach out to a bunch of different people.

Directors.

My opinion is go for current or ex leadership program members. These will be the guys that interact most with HR. Ofcourse the directors or managers are good but its hard for you to tell which ones are involved if your cold calling/emailing.