1309456-70-9Relevant articles and documents
Manganese-Catalyzed Sustainable Synthesis of Pyrroles from Alcohols and Amino Alcohols
Kallmeier, Fabian,Dudziec, Beata,Irrgang, Torsten,Kempe, Rhett
, p. 7261 - 7265 (2017)
The development of reactions that convert alcohols into important chemical compounds saves our fossil carbon resources as alcohols can be obtained from indigestible biomass such as lignocellulose. The conservation of our rare noble metals is of similar importance, and their replacement by abundantly available transition metals, such as Mn, Fe, or Co (base or nonprecious metals), in key technologies such as catalysis is a promising option. Herein, we report on the first base-metal-catalyzed synthesis of pyrroles from alcohols and amino alcohols. The most efficient catalysts are Mn complexes stabilized by PN5P ligands whereas related Fe and Co complexes are inactive. The reaction proceeds under mild conditions at catalyst loadings as low as 0.5 mol %, and has a broad scope and attractive functional-group tolerance. These findings may inspire others to use Mn catalysts to replace Ir or Ru complexes in challenging dehydrogenation reactions.
A sustainable catalytic pyrrole synthesis
Michlik, Stefan,Kempe, Rhett
, p. 140 - 144 (2013)
The pyrrole heterocycle is a prominent chemical motif and is found widely in natural products, drugs, catalysts and advanced materials. Here we introduce a sustainable iridium-catalysed pyrrole synthesis in which secondary alcohols and amino alcohols are deoxygenated and linked selectively via the formation of C-N and C-C bonds. Two equivalents of hydrogen gas are eliminated in the course of the reaction, and alcohols based entirely on renewable resources can be used as starting materials. The catalytic synthesis protocol tolerates a large variety of functional groups, which includes olefins, chlorides, bromides, organometallic moieties, amines and hydroxyl groups. We have developed a catalyst that operates efficiently under mild conditions.
A nitrogen-ligated nickel-catalyst enables selective intermolecular cyclisation of β- And γ-amino alcohols with ketones: Access to five and six-membered N-heterocycles
Singh, Khushboo,Vellakkaran, Mari,Banerjee, Debasis
supporting information, p. 2250 - 2256 (2018/05/30)
Owing to the great demand for the synthesis of N-heterocycles, development of new reactions that utilise renewable resources and convert them into key chemicals using non-precious base metal-catalysts is highly desirable. Herein, we demonstrated a sustainable Ni-catalysed dehydrogenative approach for the synthesis of pyrroles, pyridines, and quinolines by the reaction of β- and γ-amino alcohols with ketones via C-N and C-C bond formations in a tandem fashion. A variety of aryl, hetero-aryl, and alkyl ketones having free amine, halide, alkyl, alkoxy, alkene, activated benzyl, and pyridine moieties were converted into synthetically interesting 2,3 and 2,3,5-substituted bicyclic as well as tricyclic N-heterocycles with up to 90% yields. As a highlight, we demonstrated the synthesis of an interesting pyrrole derivative by intermolecular cyclisation of a steroid hormone with phenylalaninol.
The synthesis of pyrroles via acceptorless dehydrogenative condensation of secondary alcohols and 1,2-amino alcohols mediated by a robust and reusable catalyst based on nanometer-sized iridium particles
Forberg, Daniel,Obenauf, Johannes,Friedrich, Martin,Hühne, Sven-Martin,Mader, Werner,Motz, Günter,Kempe, Rhett
, p. 4188 - 4192 (2015/01/09)
Pyrroles are important compounds with several applications in medicine and material science. They can be synthesized sustainably from secondary alcohols and amino alcohols. Hydrogen and water are liberated in the course of this reaction. Here, we present that this sustainable catalytic pyrrole synthesis can be mediated efficiently by a novel iridium nanoparticle catalyst. The catalyst synthesis starts from molecular precursors, an N-ligand stabilized Ir complex and a commercially available polysilazane. The generation of nanometer-sized iridium particles was achieved (due to the presence of N atoms in the support). The robust nature of the support allows reuse of the catalyst. The scope of the reaction was verified by the synthesis of 23 pyrrole derivatives (up to 93% isolated yield). Thus, an attractive functional group tolerance (e.g. amines and olefins) could be observed. Commercially available heterogeneous Ir catalysts are inefficient in this pyrrole synthesis and extremely limited in terms of reusability.
