SL Green Realty Corp. is opening its new $3.3 billion office skyscraper Monday, in a neighborhood that’s among Manhattan’s busiest -- but is now still unusually quiet. The first tenants at One Vanderbilt, across from Grand Central Terminal, will start moving in by year’s end, SL Green President Marc Holliday said in an interview with Bloomberg Television. The tower’s big reveal comes at an awkward time for New York as many of the city’s workers stay home for fear of contracting the coronavirus.