Recoverable chiral salen complexes for asymmetric catalysis: recent progress

Abstract

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.

Enantioselective Incorporation of CO2: Status and Potential

“…For example, asymmetric NHCs 113 and salen complexes 114 are attractive to develop catalysts for enantioselective CO2 incorporation to form cyclic carbamates. The transformation of prochiral amino-and hydroxyl-oxetanes to carbamates and carbonates (Scheme 21B) 99 is an example of a symmetric reaction that may be made asymmetric through introduction of a chiral catalyst (Scheme …”

Salophen and salen oxo vanadium complexes as catalysts of sulfides oxidation with H2O2: Mechanistic insights

“…In addition, stereogenic centers or other elements of chirality can be also introduced. Moreover after appropriate modification heterogeneous catalysts [23] can be prepared.…”

New Pathway for Heterogenization of Molecular Catalysts by Non-covalent Interactions with Carbon Nanoreactors

“…The scope of reactions catalysed by metal-salen complexes is extremely wide and includes carbon-carbon bond formation, heteroatom-heteroatom bond formation and carbon-heteroatom bond formation reactions. [14] We have synthesised the fullerenetagged Cu(II) salen complex 1 ( Figure 1) in six steps according to our recently reported procedure. [15] The analogous fullerene-free complex 2 was prepared for comparison.…”