Rh<sub>2</sub>
(<i>S</i>
-1,2-NTTL)<sub>4</sub>
: A Novel Rh<sub>2</sub>
(<i>S</i>
-PTTL)<sub>4</sub>
Analog With Lower Ligand Symmetry for Asymmetric Synthesis of Chiral Cyclopropylphosphonates
作者:Frady G. Adly、Johncarlo Maddalena、Ashraf Ghanem
DOI:10.1002/chir.22349
日期:2014.11
2‐naphthaloyl‐(S)‐amino acid ligands. In terms of enantioselectivity, Rh2(S‐1,2‐NTTL)4 (3a) derived from N‐1,2‐naphthaloyl‐(S)‐tert‐leucine, was the best‐performing catalyst among the new series in the enantioselective synthesis of cyclopropylphosphonate derivatives (up to >99% enantiomeric excess). A predictive model was proposed to justify the observed high enantiomeric induction exhibited by Rh2(S‐1,2‐NTTL)4
Enantioselective Synthesis of Cyclopropylphosphonates Containing Quaternary Stereocenters Using a <i>D</i><sub>2</sub>-Symmetric Chiral Catalyst Rh<sub>2</sub>(<i>S</i>-biTISP)<sub>2</sub>
作者:Huw M. L. Davies、Gene H. Lee
DOI:10.1021/ol049525c
日期:2004.6.1
Rh-2(SbiTISP)(2)-catalyzed reactions of dimethyl aryldiazomethylphosphonates generate donor/acceptor-substituted rhodium carbenoid intermediates capable of cyclopropanation of styrenes in high yields (85-96%), diastereoselectivity (greater than or equal to98% de), and enantioselectivity (76-92% ee).