Design and Synthesis of Novel Chiral Dirhodium(II) Carboxylate Complexes for Asymmetric Cyclopropanation Reactions

作者：Adly Frady G; Gardiner Michael G; Ghanem Ashraf^*

来源：Chemistry - A European Journal, 2016, 22(10): 3447-3461.

DOI：10.1002/chem.201504817

• asymmetric synthesis
• carbenoids
• chiral catalysis
• cyclopropanation
• rhodium

A novel approach to the design of dirhodium(II) tetracarboxylates derived from (S)-amino acid ligands is reported. The approach is founded on tailoring the steric influences of the overall catalyst structure by reducing the local symmetry of the ligand's N-heterocyclic tether. The application of the new approach has led to the uncovering of [Rh-2(S-(PTTL)-P-tert)(4)] as a new member of the dirhodium(II) family with extraordinary selectivity in cyclopropanation reactions. The stereoselectivity of [Rh-2(S-(PTTL)-P-tert)(4)] was found to be comparable to that of [Rh-2(S-PTAD)(4)] (up to >99% ee), with the extra benefit of being more synthetically accessible. Correlations based on X-ray structures to justify the observed enantioinduction are also discussed.

• 出版日期2016-3-1