With the mayoral election in less than two years, business and real estate leaders are pressing State Board of Regents Chancellor Merryl Tisch to enter the race. Some fear the field is packed with left-wing Democrats like Chris Quinn, Bill de Blasio, Bill Thompson and Scott Stringer, and they see Tisch as an independent-minded alternative. Jumping in late is not out of the question for a member of the wealthy Tisch family.