Other big sales include Invesco Real Estate’s purchase of 75 Clinton in Brooklyn Heights for $50.8 million, or roughly $686,000 a unit; Invesco also bought the Arias Park Slope at 150 Fourth Avenue for $57.5 million, or roughly $605,000 a unit. Equity Residential, led by Sam Zell, bought 175 Kent Avenue for $76 million, or nearly $673,000 a unit.

“Just two years ago, buyers in Williamsburg faced trouble closing on their condominiums because banks saw the Brooklyn market as declining,” said David Behin, a partner and president of investment sales and capital advisory at the brokerage firm MNS. “There has since been a dramatic shift from stalled construction sites and concern that there was too much inventory, to significant demand from investors.”

In the case of 111 Kent, the original developer had intended the building to be a condominium, but after constructing the majority of the building, financing dried up and Stellar Management and its partner Largo Investments acquired the property for $24.6 million. Stellar invested $8 million to finish the building and quickly rented out the units, some for as high as $70 a square foot, said Mathew Lembo, a vice president at Stellar. Then, earlier this month, Stellar sold the investment to American Realty Advisors, which plans to hold the property for the long term.

“From a price standpoint, you get more value in Brooklyn than you can achieve in Manhattan,” said Stanley L. Iezman, the chairman and chief executive of American Realty Advisors. The company had been looking for two to three years in the borough before finding 111 Kent, and is continuing to search for other retail or multifamily properties in the area, he said.

Another factor that is attracting these investors to Brooklyn is that the bulk of the stalled condominium sites come with 15-year tax abatements as part of the 421A tax program. The tax program allows landlords to pay less real estate taxes over the life of the program. In return, developers are allowed to charge market rate for the rentals, but they can only increase those rents by a limited percentage each year, as set by the New York City Rent Guidelines Board.

Since many of the projects were originally intended as condominiums, there is also the possibility that should the market shift they could be converted back into for-sale units. In many cases, the projects already have condominium plans filed with the attorney general’s office or have condominium-level finishes and amenities.

One caveat is that those projects that have the 421A tax abatement must wait until the program runs down before the building can be converted back to condominiums.