Propanoyl-iron complexes chiral

Asymmetric aldol reactions are also possible with chiral propanoyl-iron complexes, as shown in Scheme 62. ° Good to excellent stereoselectivities for anti aldol products (140) are obtained when the lithium enolate of the propanoyl-iron complex is treated with 3 equiv. of EtaAlCl at -40 °C, followed by an aldehyde at -100 °C. Interestingly the same reaction using CuCN instead of Et2AlCl provides exclusively syn aldol products (141). 

Aldol Additions of Enolatcs of Chiral Iron-Propanoyl Complexes... 

---