Complex sentence: He was involved in a large number of profitable land transactions in the land speculation frenzy that the orderly Adelaide real estate market had become, notably the sale of a block on Rundle Street to a consortium of Jewish businessmen, including M. L. Marks for their Synagogue.
Split into simpler sentences: He was involved in a large number of profitable land transactions in the land speculation frenzy that the orderly Adelaide real estate market had become. One was the sale of a block on Rundle Street to a consortium of Jewish businessmen, including M. L. Marks for their Synagogue.