- Stereoselective Preparation of C-Aryl Glycosides via Visible-Light-Induced Nickel-Catalyzed Reductive Cross-Coupling of Glycosyl Chlorides and Aryl Bromides
-
A nickel-catalyzed cross-coupling reaction of glycosyl chlorides with aryl bromides has been developed. The reaction proceeds smoothly under visible-light irradiation and features the use of bench-stable glycosyl chlorides, allowing the highly stereoselective synthesis of C-aryl glycosides. (Figure presented.).
- Mou, Ze-Dong,Wang, Jia-Xi,Zhang, Xia,Niu, Dawen
-
supporting information
p. 3025 - 3029
(2021/05/27)
-
- Dearomative Photocatalytic Construction of Bridged 1,3-Diazepanes
-
The construction of diverse sp3-rich skeletal ring systems is of importance to drug discovery programmes and natural product synthesis. Herein, we report the photocatalytic construction of 2,7-diazabicyclo[3.2.1]octanes (bridged 1,3-diazepanes) via a reductive diversion of the Minisci reaction. The fused tricyclic product is proposed to form via radical addition to the C4 position of 4-substituted quinoline substrates, with subsequent Hantzsch ester-promoted reduction to a dihydropyridine intermediate which undergoes in situ two-electron ring closure to form the bridged diazepane architecture. A wide scope of N-arylimine and quinoline derivatives was demonstrated and good efficiency was observed in the construction of sterically congested all-carbon quaternary centers. Computational and experimental mechanistic studies provided insights into the reaction mechanism and observed regioselectivity/diastereoselectivity.
- Dixon, Darren J.,Duarte, Fernanda,Leitch, Jamie A.,Rogova, Tatiana
-
supporting information
p. 4121 - 4130
(2020/02/05)
-
- Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using Langlois reagent
-
Trifluoromethylation of vinylcyclopropanes (VCPs) has been developed under mild reaction conditions to synthesize allylic trifluoromethylated derivatives with high yield and E/Z selectivity using visible light photo-redox catalysis and Langlois reagent (CF3SO2Na) as a trifluoromethylation source. Further, we demonstrate a gram scale synthesis procedure for a trifluoromethylation of vinylcyclopropane.
- Chandu, Palasetty,Ghosh, Krishna Gopal,Das, Debabrata,Sureshkumar, Devarajulu
-
-
- Photocatalytic Reductive Formation of α-Tertiary Ethers from Ketals
-
A general photocatalytic reductive strategy for the construction of unsymmetrical α-tertiary dialkyl ethers is reported. By merging Lewis acid-mediated ketal activation and visible-light photocatalytic reduction, in situ-generated α-alkoxy radicals were found to engage in addition reactions with a variety of olefinic partners. Good reaction efficiency is demonstrated with a range of ketals of aromatic and aliphatic ketones. Extension to acetal substrates is also described, demonstrating the overall synthetic utility of this methodology for complex ether synthesis.
- Rossolini, Thomas,Ferko, Branislav,Dixon, Darren J.
-
supporting information
p. 6668 - 6673
(2019/09/03)
-
- Photocatalytic Three-Component Umpolung Synthesis of 1,3-Diamines
-
A visible-light-mediated photocatalytic umpolung synthesis of 1,3-diamines from in situ-generated imines and dehydroalanine derivatives is described. Pivoting on a key nucleophilic addition of photocatalytically generated α-amino radicals to electron-deficient alkenes, this three-component coupling reaction affords 1,3-diamines efficiently and diastereoselectively. The mild protocol tolerates a wide variety of functionalities including heterocycles, pinacol boronates, and aliphatic chains. Application to biologically relevant α-amino-γ-lactam synthesis and extension to 1,3-aminoalcohols is also demonstrated.
- Rossolini, Thomas,Leitch, Jamie A.,Grainger, Rachel,Dixon, Darren J.
-
supporting information
p. 6794 - 6798
(2018/10/24)
-
- Chemical modification of dehydrated amino acids in natural antimicrobial peptides by photoredox catalysis
-
Dehydroalanine (Dha) and dehydrobutyrine (Dhb) are remarkably versatile non-canonical amino acids often found in antimicrobial peptides. This work presents the selective modification of Dha and Dhb in antimicrobial peptides through photocatalytic activation of organoborates under the influence of visible light. Ir(dF(CF3)ppy)2(dtbbpy)PF6 was used as a photoredox catalyst in aqueous solutions for the modification of thiostrepton and nisin. The mild conditions and high selectivity for the dehydrated residues show that photoredox catalysis is a promising tool for the modification of peptide-derived natural products.
- Bruijn, A. Dowine De,Roelfes, Gerard
-
supporting information
p. 11314 - 11318
(2018/10/21)
-
- The coupling of potassium organotrifluoroborates with Baylis–Hillman derivatives via visible-light photoredox catalysis
-
Catalyzed by Ir[dF(CF3)ppy]2(dtbbpy)PF6, the coupling of potassium organotrifluoroborates with Baylis–Hillman derivatives under visible light irradiation has been developed. Based on the mechanism of reductive quenching cycle, it provides an easy, mild, efficient method for the synthesis of a variety of α,β-unsaturated carboxylic esters derivatives in a broad scope of the substrates.
- Ye, Hongqiang,Ye, Qianwen,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
-
supporting information
p. 2046 - 2049
(2018/05/04)
-
- Microwave-Assisted Synthesis of Heteroleptic Ir(III)+ Polypyridyl Complexes
-
We report a rapid, one-pot, operationally simple, and scalable preparation of valuable cationic heteroleptic iridium(III) polypyridyl photosensitizers. This method takes advantage of two consecutive microwave irradiation steps in the same reactor vial, avoiding the need for additional reaction purifications. A number of known heteroleptic iridium(III) complexes are prepared in up to 96% yield. Notably, this method is demonstrated to provide the synthetically versatile photosensitizer [Ir(ppy)2(dtbbpy)]PF6 in >1 g quantities in less than 5 h of bench time. We envision this method will help accelerate future developments in visible-light-dependent chemistry.
- Monos, Timothy M.,Sun, Alexandra C.,McAtee, Rory C.,Devery, James J.,Stephenson, Corey R. J.
-
p. 6988 - 6994
(2016/08/30)
-
- Effects of Molecular Oxygen, Solvent, and Light on Iridium-Photoredox/Nickel Dual-Catalyzed Cross-Coupling Reactions
-
In order to achieve reproducibility during iridium-photoredox and nickel dual-catalyzed sp3-sp2 carbon-carbon bond-forming reactions, we investigated the role that molecular oxygen (O2), solvent and light-source (CF lamp o
- Oderinde, Martins S.,Varela-Alvarez, Adrian,Aquila, Brian,Robbins, Daniel W.,Johannes, Jeffrey W.
-
p. 7642 - 7651
(2015/08/18)
-
- Facile synthesis and complete characterization of homoleptic and heteroleptic cyclometalated Iridium(III) complexes for photocatalysis
-
Herein we describe an improved synthesis for homoleptic iridium(III) 2-phenylpyridine based photocatalysts that allows rapid access to these compounds in good to high yields which have recently become a vital component within the field of catalysis. In addition, we synthesized a number of heteroleptic iridium(III) 2-phenylpyridine photocatalysts and report their photophysical and electrochemical properties. The emission energies span the range of 473-560 nm and reduction potentials from -2.27 V to -1.23 V and oxidation potentials ranging from 1.81 V to 0.69 V. Additionally, we provide the calculated excited state properties and comment on the role of these properties in designing catalytic cycles.
- Singh, Anuradha,Teegardin, Kip,Kelly, Megan,Prasad, Kariate S.,Krishnan, Sadagopan,Weaver, Jimmie D.
-
-