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.
Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Lavinia
L
Panella
Alicia Marco
AM
Aleixandre
Gerlof J
GJ
Kruidhof
Jort
J
Robertus
Ben L
BL
Feringa
Johannes G
JG
de Vries
Adriaan J
AJ
Minnaard
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