Enantioselective Rh-catalyzed hydrogenation of N-formyl dehydroamino esters with monodentate phosphoramidite ligands.
Enantioselectivities up to >99% ee were achieved in the rhodium-catalyzed asymmetric hydrogenation of N-formyl dehydroamino esters using monodentate phosphoramidites as chiral ligands. The substrates were synthesized by condensation of methyl isocyanoacetate with a range of aldehydes and with cyclohexanone. A highly convenient multigram scale one step synthesis of methyl 2-(formamido)acrylate was developed. This compound was used in the synthesis of methyl 2-(formamido)cinnamate via a solvent free Heck reaction. Moreover, full conversion and >99% ee were obtained in 1 h in the hydrogenation of methyl 2-(formamido)acrylate with 0.2 mol % catalyst and 2 bar hydrogen pressure. The versatility of the formyl protection was established by its removal under mild conditions.
Panella
Lavinia
L
Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Aleixandre
Alicia Marco
AM
Kruidhof
Gerlof J
GJ
Robertus
Jort
J
Feringa
Ben L
BL
de Vries
Johannes G
JG
Minnaard
Adriaan J
AJ
D000179:Acrylates / Q000138:chemical synthesis / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry; D000596:Amino Acids / Q000138:chemical synthesis*; D002384:Catalysis; D002934:Cinnamates / Q000138:chemical synthesis / Q000737:chemistry; D004952:Esters; D005559:Formamides / Q000138:chemical synthesis / Q000737:chemistry; D006865:Hydrogenation; D008024:Ligands; D009943:Organophosphorus Compounds / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
D000179:Acrylates; D000447:Aldehydes; D000596:Amino Acids; D002934:Cinnamates; D004952:Esters; D005559:Formamides; D008024:Ligands; D009943:Organophosphorus Compounds; C516075:methyl 2-(formamido)acrylate; C516076:methyl 2-(formamido)cinnamate; C434331:phosphoramidite; D012238:Rhodium