20279-29-2Relevant articles and documents
Insight into the Mechanism of the Acylation of Alcohols with Acid Anhydrides Catalyzed by Phosphoric Acid Derivatives
Hayashi, Hiroyuki,Yasukochi, Shotaro,Sakamoto, Tatsuhiro,Hatano, Manabu,Ishihara, Kazuaki
, p. 5197 - 5212 (2021/04/12)
Insight into the mechanism of a safe, simple, and inexpensive phosphoric acid (H3PO4)-catalyzed acylation of alcohols with acid anhydrides is described. The corresponding in situ-generated diacylated mixed anhydrides, unlike traditionally proposed monoacylated mixed anhydrides, are proposed as the active species. In particular, the diacylated mixed anhydrides act as efficient catalytic acyl transfer reagents rather than as Br?nsted acid catalysts simply activating acid anhydrides. Remarkably, highly efficient phosphoric acid (1-3 mol %)-catalyzed acylation of alcohols with acid anhydrides was achieved and a 23 g scale synthesis of an ester was demonstrated. Also, phosphoric acid catalyst was effective for synthetically useful esterification from carboxylic acids, alcohols, and acid anhydride. Moreover, with regard to recent developments in chiral 1,1′-bi-2-naphthol (BINOL)-derived phosphoric acid diester catalysts toward asymmetric kinetic resolution of alcohols by acylation, some phosphate diesters were examined. As a result, a 31P NMR study and a kinetics study strongly supported not only the acid-base cooperative mechanism as previously proposed by other researchers but also the mixed anhydride mechanism as presently proposed by us.
Palladium-Catalyzed Aerobic Oxidative Coupling of Amides with Arylboronic Acids by Cooperative Catalysis
Li, Yue,Wu, Hongxiang,Zeng, Zhuo
supporting information, p. 4357 - 4361 (2019/07/09)
The first fluoride and palladium co-catalyzed conversion of amide to ester through an aerobic oxidative coupling pathway is reported. This new approach presents a practical process that employs easily available oxygen and commercially available arylboronic acids as coupling partners, uses a wide range of N- tosylamides, and proceeds under mild reaction conditions. This protocol demonstrates broad functional group tolerance, and provides an alternative option to synthesize esters from N-tosylamides which obtained by simply N-functionalization of secondary amides.
DMAP-based flexible polymer networks formed via Heck coupling as efficient heterogeneous organocatalysts
Xu, Wei,Xia, Wu,Guan, Yukun,Wang, Yiming,Lu, Cuifen,Yang, Guichun,Nie, Junqi,Chen, Zuxing
, p. 15 - 21 (2016/06/14)
Two DMAP-based flexible polymer networks TPB-DMAP and TPA-DMAP have been successfully synthesized via palladium catalyzed Heck cross-coupling. The structures of these polymers were confirmed by solid state 13C CP/MAS and Fourier transform infrared spectroscopy (FTIR). Although both polymers have negligible surface areas, they exhibit excellent catalytic efficiency for the acylation of 1-phenylethanol with acetic anhydride due to their good swelling capacities. Utilized as a typical catalyst, the polymer TPA-DMAP shows high activities for acylation of a variety of alcohols to the corresponding esters. Moreover, the catalyst can be recycled at least ten times without obvious loss of catalytic activity.
The insertion of arynes into the O-H bond of aliphatic carboxylic acids
Wen, Chunxiao,Chen, Qian,He, Zhenwen,Yan, Xinxing,Zhang, Changyuan,Du, Zhiyun,Zhang, Kun
supporting information, p. 5470 - 5473 (2015/09/15)
The insertion of arynes into the O-H bond of aliphatic carboxylic acids promoted by sodium carboxylates is described. The reactions led to the formation of aryl carboxylates in good yields with good chemoselectivities under mild conditions.
Conjugate reduction of α,β-unsaturated esters and amides with tributyltin hydride in the presence of magnesium bromide diethyl etherate
Hirasawa, Satomi,Tajima, Yoshie,Kameda, Yoko,Nagano, Hajime
, p. 10930 - 10938 (2008/02/12)
We report herein that the conjugate reduction of α,β-unsaturated esters and amides, such as aryl acrylates, pantolactone esters of acrylic acids, diethyl itaconate and N-crotonylcamphorsultam, with tributyltin hydride proceeded in moderate to high yields in the presence of magnesium bromide diethyl etherate. The effect of metal halide enhancing the yields is also described.
Erbium(III) chloride: A very active acylation catalyst
Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Oliverio, Manuela,Procopio, Antonio,Russo, Beatrice,Tocci, Amedeo
, p. 75 - 79 (2008/02/10)
Erbium(iii) chloride is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides (Ac 2O, (EtCO)2O, (PriCO)2O, (Bu tCO)2O, and (CF3CO)2), without isomerization of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity. CSIRO 2007.
Conjugate reduction of aryl acrylates with tributyltin hydride in the presence of magnesium bromide diethyl etherate
Hirasawa, Satomi,Nagano, Hajime,Kameda, Yoko
, p. 2207 - 2209 (2007/10/03)
The conjugate reduction of aryl acrylates performed with tributyltin hydride in the presence of magnesium bromide diethyl etherate in dichloromethane gave the corresponding saturated esters in moderate to high yields. The reduction of α-methylene-γ-benzyloxycarboxylic acid esters proceeded syn-selectively, but α-methylene-β-oxycarboxylic acid esters afforded reductive elimination products under the reaction conditions.
A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid
Miyashita, Mitsutomo,Shiina, Isamu,Miyoshi, So,Mukaiyama, Teruaki
, p. 1516 - 1527 (2007/10/02)
In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
A new model for dioxygen binding in hemocyanin. Synthesis, characterization, and molecular structure of the μ-η2:η2 peroxo dinuclear copper(II) complexes, [Cu(HB(3,5-R2pz)3)]2(O2) (R = i-Pr and Ph)
Kitajima, Nobumasa,Fujisawa, Kiyoshi,Fujimoto, Chisato,Moro-oka, Yoshihiko,Hashimoto, Shinji,Kitagawa, Teizo,Toriumi, Koshiro,Tatsumi, Kazuyuki,Nakamura, Akira
, p. 1277 - 1291 (2007/10/02)
The synthesis and characterization of μ-η2:η2 peroxo dinuclear copper(II) complexes which show many similarities to oxyhemocyanin (or oxytyrosinase) in their physicochemical properties are presented. The low-temperature reaction of a di-μ-hydroxo copper(II) complex [Cu(HB(3,5-i-Pr2pz)3)]2(OH)2 (8) with H2O2 gave a μ-peroxo complex [Cu(HB(3,5-i-Pr2pz)3)]2(O2) (6). Complex 6 was also prepared by dioxygen addition to a copper(I) complex Cu(HB(3,5-i-Pr2pz)3) (9). The preparation of an analogous peroxo complex [Cu(HB(3,5-Ph2pz)3)]2(O2) (7) was accomplished by the similar dioxygen treatment of a copper(I) acetone adduct Cu(Me2CO)(HB(3,5-Ph2pz)3) (10). The reaction of 6 with CO or PPh3 causes release of dioxygen, resulting in formation of the corresponding copper(I) adduct, Cu(CO)(HB(3,5-i-Pr2pz)3) (11) or Cu(PPh3)(HB(3,5-i-Pr2pz)3) (12). Crystallography was performed for 6-6(CH2Cl2), 8-1.5(CH2Cl2), and 11. Compound 6-6(CH2Cl2) crystallizes in the monoclinic space group C2/c with a = 26.36 (2) A?, b = 13.290 (4) A?, c = 29.29 (2) A?, β= 114.59 (6)°, V = 7915 (9) A?3, and Z = 4. The refinement converged with the final R (Rw) value, 0.101 (0.148), for 3003 reflections with F ≥ 3σ(Fo). Compound 8-1.5(CH2Cl2) crystallizes in the triclinic space group P1? with a = 16.466 (4) A?, b = 16.904 (5) A?, c = 14.077 (3) A?, a = 112.92 (2)°, β= 99.21 (2)°, γ = 90.76 (2)°, V = 3550 (2) A?3, Z = 2, and the final R (Rw) factor, 0.083 (0.105), for 7226 reflections with F ≥ 3σ(Fo). Compound 11 crystallizes in the monoclinic space group, P21/a with a = 16.595 (4) A?, b = 19.154 (4) A?, c = 10.359 (2) A?, β= 106.65 (2)°, V = 3155 (1) A?3, Z = 4, and the final R (Rw) value 0.083 (0.074) for 5356 reflections with F ≥ 3σ(Fo). The X-ray analysis of 6-6(CH2Cl2) definitely established the μ-η2:η2 coordination structure of the peroxide ion for the first time. This unusual side-on structure is entirely novel for a d-block element transition-metal-dioxygen complex. Both 6 and 7 show remarkable characteristics which are very similar to those known for oxyhemocyanin and oxytyrosinase. Complex 6: diamagnetic; ν(O-O), 741 cm-1; UV-vis, 349 nm (ε, 21 000), 551 nm (ε, 790); Cu-Cu, 3.56 A?. Complex 7: diamagnetic, ν(O-O), 759 cm-1; UV-vis, 355 nm (ε, 18 000), 542 nm (ε, 1040). These properties are all consistent with those of an analogous complex, [Cu(HB(3,5-Me2pz)3)]2(O2) (5), of which the characterization and reactivities were reported already (Kitajima, N., et al. J. Am. Chem. Soc. 1990, 112, 6402; 1991, 113, 5664). The magnetic and spectroscopic features of 5-7 and their biological relevance are discussed in detail. Furthermore, simple interpretation of the electronic state of the N3Cu(O22-)CuN3 chromophore is provided based on extended Hu?ckel MO calculations. The close resemblance between the properties of μ-η2:η2 peroxo complexes 5-7 and oxyhemocyanin led us to propose a new model for dioxygen binding in hemocyanin; dioxygen is simply bound between the two copper ions in the μ-η2:η2 mode. With this structural model; the existence of an endogenous bridging ligand, which has been generally supposed to account for the diamagnetism of oxyhemocyanin, is no longer necessary.
A New and Efficient Method for the Preparation of S-Phenyl Carbothioates via Mixed Anhydrides Using Active Titanium(IV) Salts
Mukaiyama, Teruaki,Miyashita, Mitsutomo,Shiina,, Isamu
, p. 1747 - 1750 (2007/10/02)
In the presence of a catalytic amount of titanium(IV) salt, various S-phenyl carbothioates are prepared in excallent yields by the reaction of nearly equimolar amounts of silyl derivatives of carboxylic acids and benzenethiols with p-trifluoromethylbenzoic anhydride.
