Heavyweight "R-SMS-Phos" ligands in the olefins' hydrogenation arena.
A series of enantiopure P-stereogenic 1,2-bis[(o-RO-phenyl)(phenyl)phosphino]ethane (R-SMS-Phos) ligands wherein R = i-Pr, i-Bu, t-Bu, 3-Pen, and CH(2)TMS was assessed in the Rh(I)-catalyzed hydrogenation of an indicative set of olefins. The best performing t-Bu-SMS-Phos ligand was screened against a wide range of representative classes of standard and new olefinic substrates such as dehydroamido esters, dehydro-alpha-amido-phosphonates, enamides, itaconates, acrylates, enol acetates, alpha-phosphonovinyl benzoates, alpha-(2-pyridyl N-oxide)styrenes, and alpha-(1-hydroxyliminoethyl)styrenes. Excellent enantioselectivities and high TOFs were attained under mild conditions.
Zupancic
Borut
B
Laboratory of Organic and Medicinal Chemistry, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.
Mohar
Barbara
B
Stephan
Michel
M