76-09-5Relevant articles and documents
Reductive coupling of phthalic anhydrides with aliphatic ketones by low-valent titanium: Unusual two-to-one coupling for preparation of 3,3-disubstituted phthalides
Kise, Naoki,Yamamoto, Shota,Sakurai, Toshihiko
, (2020)
The reductive coupling of phthalic anhydrides with acetone by Zn-TiCl4 in THF gave two-to-one and one-to-one coupled products. The coupled products were transformed to 3,3-diisopropyl-, 3-isopropylidene-, and 3-isopropylphthalides. In addition, the reductive coupling of phthalic anhydrides with acetonylacetone by Zn-TiCl4 in THF gave 3-spirocyclopentanylphtalides stereoselectively.
Deactivation and Regeneration of NaTaO3 Photocatalyst in Cooperating Dehydrogenation Coupling of Isopropanol and Hydrogenation Coupling of Acetone Reaction System
Cao, Baoyue,Yu, Yan,Xu, Shan,Wang, Xiangting,Zhang, Li,Wang, Zhijian,Wang, Shumin,Zhang, Guochun
, p. 466 - 471 (2018)
Photocatalyst activity is influenced by many factors, such as adsorption of by-products, runoff of surface hydroxyl groups and carriers. In this study, a simple and efficient photocatalyst regeneration method was developed. Results indicated that NaTaO3 photocatalyst lost its photoactivity after three cycles of reaction that involves coupling of isopropanol and hydrogenation coupling of acetone reaction system. Runoff of Na on the surface was the main reason for the deactivation of NaTaO3 photocatalyst. After hydrothermal treatment of the deactivated NaTaO3 with 10 m NaOH at 180°C for 12 h, its photocatalytic activity was restored to the original level. The photocatalytic activity remained stable even after 10 cycles.
Synthesis of Layered Carbonitrides from Biotic Molecules for Photoredox Transformations
Yang, Can,Wang, Bo,Zhang, Linzhu,Yin, Ling,Wang, Xinchen
, p. 6627 - 6631 (2017)
The construction of layered covalent carbon nitride polymers based on tri-s-triazine units has been achieved by using nucleobases (adenine, guanine, cytosine, thymine and uracil) and urea to establish a two-dimensional semiconducting structure that allows band-gap engineering applications. This biomolecule-derived binary carbon nitride polymer enables the generation of energized charge carrier with light-irradiation to induce photoredox reactions for stable hydrogen production and heterogeneous organosynthesis of C?O, C?C, C?N and N?N bonds, which may enrich discussion on chemical reactions in prebiotic conditions by taking account of the photoredox function of conjugated carbonitride semiconductors that have long been considered to be stable HCN-derived organic macromolecules in space.
Controlling Chemoselectivity of Catalytic Hydroboration with Light
Bergamaschi, Enrico,Chen, Yi-Kai,Hohenadel, Melissa,Lunic, Danijela,McLean, Liam A.,Teskey, Christopher J.
supporting information, (2022/01/13)
The ability to selectively react one functional group in the presence of another underpins efficient reaction sequences. Despite many designer catalytic systems being reported for hydroboration reactions, which allow introduction of a functional handle fo
Protodeboronation of (Hetero)Arylboronic Esters: Direct versus Prehydrolytic Pathways and Self-/Auto-Catalysis
Hayes, Hannah L. D.,Wei, Ran,Assante, Michele,Geogheghan, Katherine J.,Jin, Na,Tomasi, Simone,Noonan, Gary,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information, p. 14814 - 14826 (2021/09/13)
The kinetics and mechanism of the base-catalyzed hydrolysis (ArB(OR)2→ ArB(OH)2) and protodeboronation (ArB(OR)2→ ArH) of a series of boronic esters, encompassing eight different polyols and 10 polyfluoroaryl and heteroaryl moieties, have been investigated by in situ and stopped-flow NMR spectroscopy (19F,1H, and11B), pH-rate dependence, isotope entrainment,2H KIEs, and KS-DFT computations. The study reveals the phenomenological stability of boronic esters under basic aqueous-organic conditions to be highly nuanced. In contrast to common assumption, esterification does not necessarily impart greater stability compared to the corresponding boronic acid. Moreover, hydrolysis of the ester to the boronic acid can be a dominant component of the overall protodeboronation process, augmented by self-, auto-, and oxidative (phenolic) catalysis when the pH is close to the pKaof the boronic acid/ester.
Well-defined Cp*Co(III)-catalyzed Hydrogenation of Carbonates and Polycarbonates
Dahiya, Pardeep,Gangwar, Manoj Kumar,Sundararaju, Basker
, p. 934 - 939 (2020/12/15)
We herein report the catalytic hydrogenation of carbonates and polycarbonates into their corresponding diols/alcohols using well-defined, air-stable, high-valent cobalt complexes. Several novel Cp*Co(III) complexes bearing N,O-chelation were isolated for the first time and structurally characterized by various spectroscopic techniques including single crystal X-ray crystallography. These novel Co(III) complexes have shown excellent catalytic activity to produce value added diols/alcohols from carbonate and polycarbonates through hydrogenation using molecular hydrogen as sole reductant or iPrOH as transfer hydrogenation source. To demonstrate the developed methodology's practical applicability, we have recycled the bisphenol A monomer from compact disc (CD) through hydrogenation under the established reaction conditions using phosphine-free, earth-abundant, air- and moisture-stable high-valent cobalt catalysts.
GaN nanowires as a reusable photoredox catalyst for radical coupling of carbonyl under blacklight irradiation
Botton, Gianluigi,Cen, Yunen,Cheng, Shaobo,Li, Chao-Jun,Liu, Mingxin,Mi, Zetian,Rashid, Roksana T.,Tan, Lida
, p. 7864 - 7870 (2020/08/19)
Employing photo-energy to drive the desired chemical transformation has been a long pursued subject. The development of homogeneous photoredox catalysts in radical coupling reactions has been truly phenomenal, however, with apparent disadvantages such as the difficulty in separating the catalyst and the frequent requirement of scarce noble metals. We therefore envisioned the use of a hyper-stable III-V photosensitizing semiconductor with a tunable Fermi level and energy band as a readily isolable and recyclable heterogeneous photoredox catalyst for radical coupling reactions. Using the carbonyl coupling reaction as a proof-of-concept, herein, we report a photo-pinacol coupling reaction catalyzed by GaN nanowires under ambient light at room temperature with methanol as a solvent and sacrificial reagent. By simply tuning the dopant, the GaN nanowire shows significantly enhanced electronic properties. The catalyst showed excellent stability, reusability and functional tolerance. All reactions could be accomplished with a single piece of nanowire on Si-wafer. This journal is
Boronic, diboronic and boric acid esters of 1,8-naphthalenediol-synthesis, structure and formation of boronium salts
Krempner, Clemens,Manankandayalage, Chamila P.,Unruh, Daniel K.
supporting information, p. 4834 - 4842 (2020/04/27)
The 1,8-naphthalenediolate [1,8-O2C10H8] supported boronic and boric acid esters of general formula X-B(1,8-O2C10H8), where X = C6H5 (1a), C6F5 (2a), 3,4,5-F3-C6H2 (3a), 2,4,6-F3-C6H2 (4a), 2,6-F2-C6H3 (5a), 2,6-Cl2-C6H3 (6a), 2,4,6-Me3-C6H2 (7a), 2,6-(MeO)3-C6H3 (8a), Bun (9a), MeO (10a), OH (11a) and Cl (13a), were synthesized, NMR spectroscopically characterized, and the solid-state structures of 1a-5a, 8a and 10a determined by X-ray crystallography. The acceptor numbers of 1a-7a and 13a were determined and found to be similar to their catecholate analogues, R-Bcat, indicating similar Lewis acidities of these two classes of boronic acid esters. The reaction of B2(NMe2)4 with 1,8-naphthalenediol, followed by addition of HCl furnished the diboronic acid ester B2(1,8-O2C10H8)4 (16a) in ca. 70% yield. Cl-B(1,8-O2C10H8) (13a) was shown to react with OPEt3, DMAP, 1,10-phenanthroline and 2,2′-bipyridine, resp., to give the boronium salts [(Et3PO)2B(1,8-O2C10H8)]Cl (18a), [(DMAP)2B(1,8-O2C10H8)]Cl (22a), [(2,2′-bipyridine)B(1,8-O2C10H8)]Cl (23a) and [(1,10-phenanthroline)B(1,8-O2C10H8)]Cl (24a), which were characterized by NMR spectroscopy and X-ray crystallography.
A convenient C–H functionalization platform for pyrroloiminoquinone alkaloid synthesis
Smith, Myles W.,Falk, Isaac D.,Ikemoto, Hideya,Burns, Noah Z.
, p. 3366 - 3370 (2019/05/17)
Pyrroloiminoquinone alkaloids represent a structurally intriguing class of natural products that display an array of useful biological properties. Here, we present a versatile and scalable platform for the synthesis of this diverse family – and in particular the antitumor discorhabdins – built upon sequential selective C–H functionalization of tryptamine. The utility of this strategy is showcased through short formal syntheses of damirones A–C, makaluvamines D and I, and discorhadbin E. Additionally, we describe efforts to develop the first catalytic asymmetric entry to the discorhabdin subclass.
Oxidative Cleavage of Alkene C=C Bonds Using a Manganese Catalyzed Oxidation with H2O2 Combined with Periodate Oxidation
Mecozzi, Francesco,Dong, Jia Jia,Angelone, Davide,Browne, Wesley R.,Eisink, Niek N. H. M.
supporting information, p. 7151 - 7158 (2019/11/16)
A one-pot multi-step method for the oxidative cleavage of alkenes to aldehydes/ketones under ambient conditions is described as an alternative to ozonolysis. The first step is a highly efficient manganese catalyzed epoxidation/cis-dihydroxylation of alkenes. This step is followed by an Fe(III) assisted ring opening of the epoxide (where necessary) to a 1,2-diol. Carbon–carbon bond cleavage is achieved by treatment of the diol with sodium periodate. The conditions used in each step are not only compatible with the subsequent step(s), but also provide for increased conversion compared to the equivalent reactions carried out on the isolated intermediate compounds. The described procedure allows for carbon–carbon bond cleavage in the presence of other alkenes, oxidation sensitive moieties and other functional groups; the mild conditions (r.t.) used in all three steps make this a viable general alternative to ozonolysis and especially for use under flow or continuous batch conditions.
