Ruthenium and Iron-Catalysed Decarboxylative N-alkylation of Cyclic Α-Amino Acids with Alcohols: Sustainable Routes to Pyrrolidine and Piperidine Derivatives
A modular and waste-free strategy for constructing N-substituted cyclic amines via decarboxylative N-alkylation of α-amino acids employing ruthenium- and iron-based catalysts is presented. The reported method allows the synthesis of a wide range of five- and six-membered N-alkylated heterocycles in moderate-to-excellent yields starting from predominantly proline and a broad range of benzyl alcohols, and primary and secondary aliphatic alcohols. Examples using pipecolic acid for the construction of piperidine derivatives, as well as the one-pot synthesis of α-amino nitriles, are also shown.
Afanasenko, Anastasiia,Hannah, Rachael,Yan, Tao,Elangovan, Saravanakumar,Barta, Katalin
p. 3801 - 3807
(2019/07/31)
Ruthenium-Catalyzed Regioselective 1,4-Hydroboration of Pyridines
Simple ruthenium precursor [Ru(p-cymene)Cl2]2 1 catalyzed regioselective 1,4-dearomatization of pyridine derivatives using pinacolborane is reported. Two catalytic intermediates, [Ru(p-cymene)Cl2Py] 2 and [Ru(p-cymene)Cls
Iridium-catalyzed decarboxylative N-alkylation of α-amino acids with primary alcohols
A new decarboxylative N-alkylation reaction of α-amino acids has been developed. A variety of tertiary amines were obtained in good to excellent yields via the decarboxylative N-alkylation reaction of α-amino acids with primary alcohols catalyzed by a CpIr complex. Georg Thieme Verlag Stuttgart New York.
7-Azabicyclo[2.2.1]heptane as a scaffold for the development of selective sigma-2 (σ2) receptor ligands
A series of N-substituted 7-azabicyclo[2.2.1]heptanes (12-17 and 22-25) and similarly substituted pyrrolidines (32-36 and 41-44) were synthesized as sterically-reduced, achiral analogs of adamantane- and trishomocubane-derived σ ligands. In vitro competition binding assays against σ receptors revealed that arylalkyl N-substituents conferred selectivity for the σ2 subtype, while alicyclic or polycarbocyclic substituents imparted high affinity for both subtypes. The σ2 binding and subtype selectivities of N-arylalkyl-7-azanorbornanes was generally greater than the analogously-substituted pyrrolidines, indicating that steric bulk and conformational restriction around the nitrogen atom are likely important for subtype discrimination.
Banister, Samuel D.,Rendina, Louis M.,Kassiou, Michael
supporting information; experimental part
p. 4059 - 4063
(2012/07/03)
An efficient synthesis of nitrogen heterocycles by Cp*Ir-catalyzed N-cycloalkylation of primary amines with diols
A new efficient method for the N-cycloalkylation of primary amines with diols catalyzed by a Cp*Ir complex have been developed. A variety of five-, six-, and seven-membered cyclic amines are synthesized in good to excellent yields in environmentally benign and atom economical manner with the formation of only water as a coproduct. A large scale synthesis of N-benzylpiperidine and a two-step asymmetric synthesis of (S)-2-phenylpiperidine using (R)-1-phenylethylamine as a starting primary amine have been also achieved.
Ruthenium Complex-Catalyzed N-Heterocyclization. Syntheses of N-Substituted Pyrroles and Pyrrolidines from 1,4-Diols and Primary Amines
2-Butyne-1,4-diol reacts with aliphatic amines in the presence of a catalytic amount of at 150 deg C to give N-alkylpyrroles in good yields. 1,4-Butanediol reacts with aromatic or aliphatic amines to give N-substituted pyrrolidines in excellent yields; and are the best catalysts for aromatic and aliphatic amines, respectively.The reaction of 2-butene-1,4-diol with alkyl amines gives a 1:1 mixture of N-substituted pyrroles and pyrrolidines in high yield.