1604-01-9Relevant articles and documents
Characterization of three novel enzymes with imine reductase activity
Gand,Müller,Wardenga,H?hne
supporting information, p. 126 - 132 (2015/02/19)
Imine reductases (IRED) are promising catalysts for the synthesis of optically pure secondary cyclic amines. Three novel IREDs from Paenibacillus elgii B69, Streptomyces ipomoeae 91-03 and Pseudomonas putida KT2440 were identified by amino acid or structural similarity search, cloned and recombinantly expressed in E. coli and their substrate scope was investigated. Besides the acceptance of cyclic amines, also acyclic amines could be identified as substrates for all IREDs. For the IRED from P. putida, a crystal structure (PDB-code 3L6D) is available in the database, but the function of the protein was not investigated so far. This enzyme showed the highest apparent E-value of approximately Eapp = 52 for (R)-methylpyrrolidine of the IREDs investigated in this study. Thus, an excellent enantiomeric purity of >99% and 97% conversion was reached in a biocatalytic reaction using resting cells after 24 h. Interestingly, a histidine residue could be confirmed as a catalytic residue by mutagenesis, but the residue is placed one turn aside compared to the formally known position of the catalytic Asp187 of Streptomyces kanamyceticus IRED.
Use of group 4 Bis(sulfonamido) complexes in the intramolecular hydroamination of alkynes and allenes
Ackermann, Lutz,Bergman, Robert G.,Loy, Rebecca N.
, p. 11956 - 11963 (2007/10/03)
Titanium tetrakis(amido) complexes catalyze the intramolecular hydroamination of alkynes and allenes more efficiently than Cp-based species. We report here that electron-withdrawing and sterically demanding bis(sulfonamido) ligands lead to enhanced catalytic activity. Zirconium analogues have also been prepared, and the tosyl-substituted complex 20 has been structurally characterized. As in the titanium series, bis(sulfonamido) zirconium catalysts are more efficient in the intramolecular hydroamination of allenes than bis(cyclopentadienyl) complex Cp2ZrMe2 (23). Furthermore, these compounds transform 1,3-disubstituted aminoallenes with high stereoselectivity to the Z-allylamines and allow the hydroamination of a trisubstituted allene. Titanium bis(sulfonamido) imido complex 27 was synthesized. It converts aminoallene 10 to cylic imine 11 with a rate comparable to that of tetrakis(amide) 15, supporting the hypothesis of a catalytically active titanium imido intermediate.
Short Enantioselective Total Syntheses of the Piperidine Alkaloids (S)-Coniine and (2R,6R)-trans-Solenopsin A via Catalytic Asymmetric Imine Hydrosilylation
Reding, Matthew T.,Buchwald, Stephen L.
, p. 6344 - 6347 (2007/10/03)
The enantioselective syntheses of (S)-coniine and (2R,6R)-trans-solenopsin A are reported. The key step in both syntheses is the catalytic asymmetric hydrosilylation of a cyclic imine.
