var myMockBOC = new Mock<BusinessObjectContext>(null, null);
This will pass nulls in for your two parameters.
Another approach would be to create an internal constructor meant for test usage only, and use InternalsVisibleTo to allow your test assembly to use it. Unfortunately this has a big drawback in that if you sign your assemblies, Moq is unable to use the constructor. This is supposed to be addressed in the 4.0 release of Moq though.