Green assembles parcel for new midtown tower.

While a string of major developers have secured development parcels on the West Side, where the city has put together a tax incentive plan to spur the area's conversion into an extension of Midtown, others have passed up the neighborhood in favor of more established office districts.

Joining a list of big names in the industry with parcels that can accommodate major new office towers, SL Green has almost finished assembling the small square block bounded by 42nd and 43rd Street, Madison Avenue and Grand Central Terminal. With its purchase of 331 Madison Avenue in recent weeks, a 90,000 s/f building on the northwest corner of the block, the company now owns three of the four properties on the postage stamp of land, which company sources say would allow for a 1 million s/f tower with four sides of block front retail.

To have the whole block, SL Green, of course, still must acquire 51 East 42nd Street, a property on the site's eastern edge owned by Maritime Investments Company. The other three buildings, 331 Madison, 33 East 42nd Street and 48 East 43rd Street, also have leases in place that would prevent SL Green from clearing the properties in the immediate term for construction.

"We plan to operate the buildings as they are for now, but the site will be an opportunity in the future," said Steve Durels, SL Green's executive vice president and director of leasing.

Durels indicated that the company hadn't been focusing on opportunities to build on the West Side, a decision that is likely reflective of the tastes of tenants.

Large space users haven't been willing yet to venture to an office district that, right now, remains only a vision, despite predictions by real estate experts and city officials of the West Side's eventual ascendancy into an essential expansion of Midtown that will alleviate the district's budding space shortage. Although there are millions of square feet of planned projects on the West Side, few have been able to break ground because of the lack of tenant commitment. Developers with prime parcels located elsewhere, on the other hand, have been able to build on speculation because of the likelihood of success leasing the space in the current market

Macklowe Properties, for example, is building a boutique office tower at 510 Madison Avenue and has an office project planned for the site of the Drake Hotel. The hesitancy and caution that developers are showing on the West Side reveals that the traditional framework of criteria that has determined which areas of the city are viable for new office development remains unchanged for many builders--in spite of the commercial real estate market's strength. Until a large tenant commits to a development on the West Side, new buildings, it seems, will sprout, where limited opportunities permit, in bustling, established districts that are in close proximity to transportation infrastructure.