Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess

Abstract

Asymmetric List–Mannich reactions were carried out in the frozen state to afford optically active adducts in moderate-to-good chemical yields and enantiomeric excesses (ee). The frozen solution exerts critical control of ee via entropy changes, in sharp contrast to the enthalpy-driven asymmetric reactions typically observed in homogeneous solvents. This study provides new perspectives for asymmetric syntheses and an attractive alternative to conventional media.

In situ Visualization of Ferrous Ions Dissolved from Pure Iron Wire into Thin Frozen Aqueous Solution Films by Combination of Microscopy and Image Processing

“…(4) In FCSs, some unusual chemical phenomena including the acceleration of chemical reactions under subzero conditions and dissolution of chemical species insoluble in water have been reported. (5)(6)(7)(8)(9)(10)(11)(12) These effects are attributed to the unique physicochemical properties of FCSs, induced by the microscale phase transitions at ice/solution interfaces. (13)(14)(15) The reductive reactions of metal oxides and their dissolution have also been reported to be accelerated in FCSs.…”