▼Chiral Pyrophosphoric Acid Catalysts for the para-Selective and Eanantioselective Aza-Friedel–Crafts Reaction of Phenols
Chiral BINOL-derived pyrophosphoric acid catalysts were developed and used for the regio- and enantioselective aza-Friedel–Crafts reaction of phenols with aldimines. ortho/para-Directing phenols could react at the para-position selectively with moderate to good enantioselectivities. Moreover, the gram-scale transformation of a product into the key intermediate for the antifungal agent (R)-bifonazole was demonstrated.
"Pentamethylcyclopentadienyl rhodium(III)–chiral disulfonate hybrid catalysis for enantioselective C–H bond functionalization"
Shun Satake, Takumaru Kurihara, Keisuke Nishikawa, Takuya Mochizuki, Manabu Hatano, Kazuaki Ishihara, Tatsuhiko Yoshino* & Shigeki Matsunaga*
Nat. Catal. 2018, 1(8), 585–591. Published: 23 July 2018
Press Release (August 9, 2018)
Hybrid catalyst with high enantiomer selectivity
化学 2018, 73(8), 25–28.
化学と工業 2018, 71(7), 598–601.
▼Enantioselective Aza-Friedel–Crafts Reaction of Furan with α-Ketimino Esters Induced by a Conjugated Double Hydrogen Bond Network of Chiral Bis(phosphoric Acid) Catalysts
The article was first published on 25 Jun 2018
Chem. Sci. 2018, 9(30), 6361-6367.
Chiral C2- and C1-symmetric BINOL-derived bis(phosphoric acid) catalysts, which have OP(=O)(OH)2/OP(=O)(OH)(OR) moieties at the 2,2’-positions, were developed and used for the enantioselective aza-Friedel–Crafts reaction of 2-methoxyfuran with α-ketimino esters for the first time. The intramolecular conjugated double hydrogen bond network is a key to increasing the Brønsted acidity and preventing deactivation of the catalysts. Highly functionalized α-amino acid derivatives with a chiral quaternary carbon center could be transformed into versatile optically active N- and O-heterocycles and an α-aryl-substituted serine.
Selected as a Back Cover Picture
Chem. Sci. 2018, 9(30), 6453-6454.
▼Asymmetric Total Synthesis of (−)-Maldoxin, a Common Biosynthetic Ancestor of the Chloropupukeananin Family
▼Thiourea–I2 as Lewis Base–Lewis
Acid Cooperative Catalysts for Iodochlorination of Alkene with In Situ-Generated I–Cl
Takahiro Horibe , Yasutaka Tsuji, and Kazuaki Ishihara*
ACS Catal. 2018, 8(7), 6362–6366
Publication Date (Web): June 7, 2018
有機合成化学協会誌 2018, 76(6), 563.
▼Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
Yanhui Lu, Hidefumi Nakatsuji, Yukimasa Okumura, Lu Yao, and Kazuaki Ishihara*
J. Am. Chem. Soc. 2018, 140(19), 6039-6043.
Publication Date (Web): April 30, 2018
▼ortho-Substituent Effect on 2,4-Bis(trifluoromethyl)phenylboronic Acid-Catalyzed Dehydrative Condensation between Carboxylic Acids
Ke Wang, Yanhui Lu and Kazuaki Ishihara*
Chem. Commun. 2018, 54(43), 5410–5413. (Inside Cover Picture)
The article was first published on 24 Apr 2018
▼Boron Tribromide‐Assisted Chiral Phosphoric Acid Catalysts for Enantioselective [2+2] Cycloaddition
First published: 30 March 2018
Proton challenge: BBr3‐assisted chiral phosphoric acid catalysts were used for the enantioselective [2+2] cycloaddition of vinyl sulfides with acroleins. One of the obtained [2+2] cycloadducts could be readily transformed to a key intermediate for (+)‐frontalin as a pheromone of Asian elephants.
▼Metal-Free Transesterification Catalyzed by Tetramethylammonium Methyl Carbonate
Manabu Hatano, Yuji Tabata, Yurika Yoshida, Kohei Toh, Kenji Yamashita, Yoshihiro Ogura, and Kazuaki Ishihara*
Green Chem. 2018, 20(6), 1193–1198.
Environmentally benign metal-free tetramethylammonium methyl carbonate is effective as a catalyst for the chemoselective, scalable, and reusable transesterification of various esters and alcohols in common organic solvents. In situ-generated highly active species, tetramethylammonium alkoxides, can greatly avoid the self-decomposition at ≤110 °C, and reusable. In particular, chelating substrates, such as amino alcohols, diols, triols, sugar derivatives, alkaloids, α-amino acid esters, etc., which deactivate conventional metal salt catalysts, can be used. A 100 gram scale biodiesel production was also demonstrated.
▼Enantioselective Aza-Friedel-Crafts Reaction of Indoles with Ketimines Catalyzed by Chiral Potassium Binaphthyldisulfonates
The enantioselective aza-Friedel–Crafts reaction of indoles with low-reactive ketimines has been developed in the presence of a chiral monopotassium binaphthyldisulfonate as a strong Brønsted acid catalyst. A broad substrate scope was achieved, and the corresponding 3-indolylmethanamines with a chiral quaternary carbon center were obtained in high yields with high enantioselectivities. The addition of a catalytic amount of acetic acid considerably promoted the reaction, and a gram-scale reaction could be achieved with reduced catalyst loading.