Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• hydroxamate uptake protein component A (FhuA) as host for defined Cu(I) NHC or Cu(II) terpyridyl complexes with a maleimide moiety. By covalently bonding these copper complexes to the protein artificial Diels–Alderases based on a membrane protein have been obtained. Results and Discussion Synthesis of the

• . Anchoring and refolding of the biohybrid copper complexes. Diels–Alder reaction catalyzed by the biohybrid catalysts. Supporting Information Supporting Information File 228: Illustration of the catalyst 2 and NMR spectra of synthesized compounds. Acknowledgements We gratefully acknowledge the financial

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• diazo compound 42b. The authors suggested the formation of the same chiral copper carbenoid intermediate by the reaction of the in situ prepared chiral copper complexes with both 42a and 42b to provide the observed insertion products. The reactions with phenyliodonium ylides 42a showed better ee when

• compared to that done with diazo compounds 42b. The authors attributed this observation to the large difference between the reaction temperatures, 0 °C to ylides versus 65 °C to diazo compounds. Higher temperatures increase the carbenoid formation rate by the chiral copper complexes as well as the carbene

• catalytic system. Attempts to heterogeneous catalysis using chiral copper complexes were also done. Fraile et al reported, in 2011, the copper catalyst 60 for enantioselective insertion of carbenoid into O-heterocycles C(sp3)–H bonds (Table 7) [47][48]. The reaction was performed under homogeneous and

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• Republic of China 10.3762/bjoc.12.85 Abstract A series of copper complexes (3–6) stabilized by 1,2,3-triazole-tethered N-heterocyclic carbene ligands have been prepared via simple reaction of imidazolium salts with copper powder in good yields. The structures of bi- and trinuclear copper complexes were

• fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. In particular, [Cu2(L2)2](PF6)2 (3) and [Cu2(L3)2](PF6)2 (4) were dinuclear copper complexes. Complexes [Cu3(L4)2](PF6)3 (5) and [Cu3(L5)2](PF6)3 (6) consist of a triangular Cu3 core. These structures vary depending on the

• range of 157.6–216 ppm [34][35]. Single crystal X-ray diffraction studies To obtain additional insight into the coordination and supramolecular properties, suitable single crystals of all the copper complexes were obtained for single-crystal X-ray diffraction analysis. Crystals were grown by slow

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

• -copper complexes in aqueous media. In result we could show that supramolecular structures and metal complexes open up a wide field for the development of novel stimuli-responsive polymer materials. We thus described that the simple addition of copper and γ-CD to a poly((4-hydroxy-3-(pyridin-3-yldiazenyl

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• -phenanthroline derivatives is present in the reaction mixture [80]. Although the structural characteristics of the corresponding copper complexes remain elusive, these ligands are frequently applied in CuAAC reactions, especially in macromolecular chemistry [15]. Apart from N-donor ligands, the use of phosphorus

• until NHC-copper complexes were first employed in CuAAC reactions. In 2006, the group of Nolan reported the application of air-stable complexes [(NHC)CuX] as efficient catalysts for CuAAC reactions with terminal and internal alkynes in aqueous solution or under neat conditions (Table 2) [146][147]. Also

Recent progress in the discovery of small molecules for the treatment of amyotrophic lateral sclerosis (ALS)

• Allison S. Limpert,
• Margrith E. Mattmann and
• Nicholas D. P. Cosford

Beilstein J. Org. Chem. 2013, 9, 717–732, doi:10.3762/bjoc.9.82

• (thiosemicarbazonato)copper complexes (Cu(II)(btsc)s; Figure 9), reduced stress-induced kinase activity and prevented TDP-43 aggregation [38]. Cu(II)(btsc)s have previously been demonstrated to have neuroprotective effects in mouse models of neurodegeneration [47] and elicited similar results in cells overexpressing

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• the success achieved in the procedures described above, stoichiometric use of chiral ligands is usually required. However, recently a general catalytic methodology for the enantioselective intermolecular addition of alkyllithiums has been reported, though it implies transmetalation to copper complexes

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Gold film- catalysed benzannulation by Microwave- Assisted, Continuous Flow Organic Synthesis (MACOS)

• Gjergji Shore,
• Michael Tsimerman and
• Michael G. Organ

Beilstein J. Org. Chem. 2009, 5, No. 35, doi:10.3762/bjoc.5.35

• exploring complex, multi-step catalytic processes in flow. The benzannulation reaction between aromatic carbonyls and alkynes has received increasing attention since 2002 [29][30]. This transformation has been shown to be promoted by Lewis acids, copper complexes [31] and various gold species, including Au

Asymmetric aza-Diels- Alder reaction of Danishefsky's diene with imines in a chiral reaction medium

• Bruce Pégot,
• Olivier Nguyen Van Buu,
• Didier Gori and
• Giang Vo-Thanh

Beilstein J. Org. Chem. 2006, 2, No. 18, doi:10.1186/1860-5397-2-18

• relation to the asymmetric process. Among them are: the zirconium-binaphthol complexes developed by Kobayashi et al., [8][9][10][11] the silver catalysts of phosphine peptide Schiff bases reported by Snapper and Hoveyda,[12] as well as the copper complexes of BINAP and phosphino-oxazolidines described by

• Jørgensen,[13][14] and the chiral copper complexes of phosphino sulfenyl ferrocenes reported by Carretero.[15] The catalyst systems also include the Lewis acid catalysts based on boron-BINOL complexes [16][17][18] and lastly zinc-BINOL complexes developed by Whiting et al.[19] In all the above cases