The first catalytic enantioselective 1,2-reduction of enones with 0.45 mol equiv potassium borohydride solution catalyzed by a chiralN,N′-dioxide–Sc(III) complex catalyst was accomplished under mild reaction conditions. A number of optically active allylic alcohols were obtained in good to excellent enantioselectivities (up to 95% ee) with nearly quantitative yields.
Enantioselective acyl transfer catalysts and their use in kinetic resolution of alcohols and desymmetrization of meso-diols
申请人:Birman Vladimir
公开号:US20050256150A1
公开(公告)日:2005-11-17
Novel enantioselective acylation catalysts comprising chiral derivatives of DHIP and DHIQ, having the following representative general structures are disclosed:
These new compounds are useful for resolving racemates or further enhancing the enantiomeric excess of an enantiomerically enriched composition and for desymmetrizing meso compounds.
enantioselective 1,2-reduction of α,β-unsaturated ketones has been achieved using a chiral pincer Mn catalyst. A series of PNN tridentate ligands containing benzimidazole groups were designed with ferrocene as the backbone, which coordinated with Mn to form the active catalyst. This mild process represents a general method to access chiralallyl alcohols with high catalytic activity (up to 9500 TON) and high enantioselectivity
Synthesis of <scp>Planar‐Chiral</scp> [2.2]<scp>Paracyclophane‐Based Oxazole‐Pyrimidine</scp> Ligands and Application in <scp>Nickel‐Catalyzed</scp> 1,<scp>2‐Reduction</scp> of α,<scp>β‐Unsaturated</scp> Ketones
structure and large steric hindrance performed successfully in nickel-catalyzed asymmetric 1,2-reduction of α,β-unsaturatedketones, affording the chiral allylic alcohols with up to 99% yield and 99% ee. Meanwhile, this reduction reaction could be conducted on gram-scale without loss of activity and enantioselectivity, and the chiral ligand could be conveniently recovered with high yield.