Mechanistic Insights into Cu-Catalyzed Asymmetric Aldol Reactions: Chemical and Spectroscopic Evidence for a Metalloenolate Intermediate

In situ IR spectroscopy and transmetalation experiments confirm a postulated catalytic cycle. The metalloenolate 1 describes the active intermediate in the aldol reaction catalyzed by CuF2 (S) -tol-binap (see reaction scheme). (S) -tol-binap= (S) - (−) -2, 2′-bis (di-p-tolylphosphanyl) -1, 1′-binaphthyl.