Recoverable chiral salen complexes for asymmetric catalysis: recent progress.

Chiral salen-type complexes have already been proven to be particularly useful asymmetric catalysts for the preparation of a wide range of enantioenriched products. Research for efficient recovery and recycling of such complexes is ongoing and has already demonstrated the value of these procedures in terms of atom economy and overall economical savings. Results reported in the near past (2006-2009) dealing with the use of recyclable chiral salen complexes are summarized here, classified according to the type of heterogenization procedures involved.