Can I purchase real estate that I or my corporation already owns with my account at Digital Trust?

No. This is potentially considered a prohibited transaction, per Internal Revenue Code 4975. You may not purchase a property or an interest in a property that is currently owned by any disqualified party. Per IRS Publication 590: disqualified parties include your fiduciary and members of your family (spouse, ancestor, lineal descendant, and any spouse of a lineal descendant), and more.