Practical Enantioselective Hydrogenation of α-Aryl- and α-Carboxyamidoethylenes by Rhodium(I)-{1,2-Bis[(<i>o</i>-<i>tert</i>-butoxyphenyl)(phenyl)phosphino]ethane}
作者:Barbara Mohar、Michel Stephan
DOI:10.1002/adsc.201200780
日期:——
The rhodium(I)-1,2-bis[(o-tert-butoxyphenyl)(phenyl)phosphino]ethane} [Rh(I)-(t-Bu-SMS-Phos)] catalyst system displayed prime efficiency in the hydrogenation of large series of α-amidostyrenes and α-amidoacrylates. Up to >99.9% enantiomeric excesses coupled with very high reaction rates were attained operating routinely under 1–10 bar of hydrogen at 22 °C in methanol. Examples include industrial substrates
Synthesis and Antimycobacterial Activity of 2,1′-Dihydropyridomycins
作者:Oliver P. Horlacher、Ruben C. Hartkoorn、Stewart T. Cole、Karl-Heinz Altmann
DOI:10.1021/ml300385q
日期:2013.2.14
Dihydropyridomycins 2 and 3, which lack the characteristic enol ester moiety of the potent antimycobacterial natural product pyridomycin (1), have been prepared from L-Thr, R- and S-hydroxy isovaleric acid, and 3-pyridinecarboxaldehyde. The 2R isomer 2 shows only 4-fold lower anti-Mtb activity than 1, indicating that the enol ester moiety in the natural product is not critical for its biological activity. This finding establishes 2 as a potent and more practical lead for anti-TB drug discovery.
Impact on Hydrogenation Catalytic Cycle of the R Groups’ Cyclic Feature in “R-SMS-Phos”
作者:Borut Zupančič、Barbara Mohar、Michel Stephan
DOI:10.1021/ol101029s
日期:2010.7.2
A series of R-SMS-Phos ligands was evaluated in the Rh(I)-catalyzed hydrogenation of a set of olefins showing a marked influence of the cyclic nature and structure of the R groups. Overall, cPen- and Cy-SMS-Phos performed efficiently, while Ph- and Bn-SMS-Phos exhibited slower kinetics and furnished lower ee's also compared with C6F5CH2-SMS-Phos. The Rh(I)-(Cy-SMS-Phos) catalyst was screened under mild conditions displaying excellent enantioselectivities and high TOFs. Cases of catalysis under catalyst or substrate control were identified.
Transition-metal-assisted asymmetric synthesis of amino acid analogs. A new synthesis of optically pure D- and L-pyridylalanines
作者:Joseph J. Bozell、C. E. Vogt、J. Gozum
DOI:10.1021/jo00007a060
日期:1991.3
BOZELL, JOSEPH J.;VOGT, C. E.;GOZUM, J., J. ORG. CHEM., 56,(1991) N, C. 2584-2587