This synagogue was burned down on November 9, 1938 by the SA and the remaining walls were demolished in January 1939.  Apparently, the whole area around that synagogue was then destroyed in air raids during 1944.

Only one of the former four major synagogues in Frankfurt was not wholly destroyed by the pogroms in November 1938 and the air raids during the Second World War: the so-called Westendsynagoge which was built from 1908 to 1910 and, after a makeshift renovation in 1950, completely reconstructed from 1989 through 1994.
Whether that was the Synagogue in which Leopold STEIN preached his Reform Judaism, and where he later formed the Westend-Union is unclear.