Abstract
A new class of dendritic monodentate phosphoramidite ligands were synthesized through substitution of the dimethylamino moiety in MonoPhos by the Fréchet-type dendritic wedge and applied in the asymmetric hydrogenation of α-dehydroamino acid esters and dimethyl itaconate. High enantioselectivities (up to 97.9% ee) and catalytic activities (up to 4850 h −1 TOF) were achieved, which are better or comparable to those obtained from MonoPhos. The third generation dendrimer catalyst gave the slightly lower catalytic activity relative to the lower generation ones. The steric shielding by the dendrimer could stabilize the rhodium complex against decomposition caused by hydrolysis in a protic solvent. The inactive catalysts (RhL 3 and RhL 4) were activated by addition of a free metal precursor Rh(COD) 2BF 4, and showed high enantioselectivities and catalytic activities.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
