Organocatalytic Enantioselective Michael Reaction of Malononitrile with β,β-Disubstituted Nitroalkenes
We have developed and optimized an enantioselective Michael reaction of malononitrile with β,β-disubstituted nitroalkenes. This reaction was catalyzed by a cinchona alkaloid derived thiourea catalyst, producing products of high yields (up to 98 %) and ste
Asymmetric friedel-crafts alkylation of α-substituted β-nitroacrylates: Access to β2,2-amino acids bearing indolic all-carbon quaternary stereocenters
A highly enantioselective Friedel-Crafts alkylation reaction of indoles with acyclic α-substituted β-nitroacrylates is developed under the catalysis of Ni(ClO4)2-bisoxazoline complex at 1 mol % catalyst loading, affording chiral indolic β-nitroesters bearing all-carbon quaternary stereocenters in excellent yields and ees of up to 97%. Transformation of one of the products to β2,2-amino ester and tetrahydro-β-carboline through nitro reduction and sequential Pictet-Spengler cyclization was exemplified.
Organocatalytic asymmetric transferhydrogenation of β-nitroacrylates: Accessing β2-amino acids
We describe a highly efficient and enantioselective Hantzsch ester mediated conjugate reduction of β-nitroacrylates that is catalyzed by a Jacobsen thiourea catalyst as a key step in a new route to optically active β2-amino acids. Copyright
Martin, Nolwenn J. A.,Cheng, Xu,List, Benjamin
supporting information; experimental part
p. 13862 - 13863
(2009/02/06)
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