853271-15-5Relevant articles and documents
Benzoxaborole Catalyst for Site-Selective Modification of Polyols
Kusano, Shuhei,Miyamoto, Shoto,Matsuoka, Aki,Yamada, Yuji,Ishikawa, Ryuta,Hayashida, Osamu
supporting information, p. 1598 - 1602 (2020/02/11)
The site-selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site-selective and protecting-group-free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a–k were synthesized. In-depth analysis for the substituent effect revealed that 1i–k, bearing multiple electron-withdrawing fluoro- and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i-catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis-1,2-diol derivatives proceeded with good yield and site-selective manner.
METHOD FOR PRODUCING 1,5-ANHYDRO-1-SUBSTITUTED PHENYL-D-GLUCITOL COMPOUNDS
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Paragraph 0064, (2017/07/25)
PROBLEM TO BE SOLVED: To provide a novel method for producing 1,5-anhydro-1-substituted phenyl-D-glucitol compounds useful as medicines having the action of inhibiting sodium-dependent glucose cotransporters 1. SOLUTION: The present invention provides a method for producing 1,5-anhydro-1-substituted phenyl-D-glucitol compounds represented by formula (XI), wherein, compounds represented by formula (II) are converted through a plurality of steps to produce the compounds represented by formula (XI). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
Copper-Catalyzed Amino Lactonization and Amino Oxygenation of Alkenes Using O-Benzoylhydroxylamines
Hemric, Brett N.,Shen, Kun,Wang, Qiu
supporting information, p. 5813 - 5816 (2016/06/09)
A copper-catalyzed amino lactonization of unsaturated carboxylic acids has been achieved as well as the analogous intermolecular three-component amino oxygenation of olefins. The transformation features mild conditions and a remarkably broad substrate sco
Synthesis of Multisubstituted Triphenylenes and Phenanthrenes by Cascade Reaction of o-Iodobiphenyls or (Z)-β-Halostyrenes with o-Bromobenzyl Alcohols through Two Sequential C-C Bond Formations Catalyzed by a Palladium Complex
Iwasaki, Masayuki,Araki, Yasuhiro,Iino, Shohei,Nishihara, Yasushi
, p. 9247 - 9263 (2015/09/28)
o-Bromobenzyl alcohol has been developed as a novel annulating reagent, bearing both nucleophilic and electrophilic substituents, for the facile synthesis of polycyclic aromatic hydrocarbons. A palladium/electron-deficient phosphine catalyst efficiently coupled o-iodobiphenyls or (Z)-β-halostyrenes with o-bromobenzyl alcohols to afford triphenylenes and phenanthrenes, respectively. The present cascade reaction proceeded through deacetonative cross-coupling and sequential intramolecular cyclization. An array of experimental data suggest that the reaction mechanism involves the equilibrium of 1,4-palladium migration.
Substitution controlled functionalization of ortho -bromobenzylic alcohols via palladium catalysis: Synthesis of chromenes and indenols
Mahendar, Lodi,Satyanarayana, Gedu
, p. 2059 - 2074 (2014/04/03)
An efficient domino Pd-catalyzed transformation of simple ortho-bromobenzyl tertiary alcohols to chromenes is presented. Their formation is believed to proceed via the formation of a five-membered palladacycle, which, in turn, involves in an intermolecular homocoupling with the second ortho- bromobenzyltertiary alcohol to yield the homo-biaryl bond followed by intramolecular C-O bond formation. Interestingly, when there is an allylic substituent on the benzylic carbon atom, a chemoselective switch was observed, which preferred intramolecular Heck coupling and gave indenols. Further, it has been confirmed that the tertiary alcohol functionality is indispensible to give the coupled products, whereas the use of primary/secondary benzylic alcohols furnished the simple carbonyl products via a possible reductive debromination followed by oxidation due to the availability of β-hydrogen(s).
Palladium-catalyzed annulation of o-iodobiphenyls with o-bromobenzyl alcohols: Synthesis of functionalized triphenylenes via C-C and C-H bond cleavages
Iwasaki, Masayuki,Iino, Shohei,Nishihara, Yasushi
supporting information, p. 5326 - 5329 (2013/11/06)
Treatment of o-iodobiphenyls with o-bromobenzyl alcohols in the presence of cesium carbonate under palladium catalysis affords a series of highly substituted triphenylenes. The reaction involves two C-C bond formations and C-C and C-H bond cleavages. A combination of palladium and an electron-deficient phosphine ligand proves to be effective for both decarbonylative cross-coupling and intramolecular cyclization.
Pd-Catalyzed intramolecular oxyalkynylation of alkenes with hypervalent iodine
Nicolal, Stefano,Erard, Stephane,Gonzalez, Davinla Fernandez,Waser, Jerome
supporting information; experimental part, p. 384 - 387 (2010/03/04)
(Figure presented) The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benzlodoxolone-derlved hypervalent iodine reagent 3d as an alkyne transfer reagent further expands the rapidly increasing utility of hypervalent iodine reagents in catalysis and is expected to have important implications for other similar processes.
Zirconocene-mediated and/or catalyzed unprecedented coupling reactions of alkoxymethyl-substituted styrene derivatives
Ikeuchi, Yutaka,Taguchi, Takeo,Hanzawa, Yuji
, p. 4354 - 4359 (2007/10/03)
Reactions of o-(alkoxymethyl)styrene derivatives with a stoichiometric amount of zirconocenebutene complex (zirconocene equivalent, "Cp 2Zr") brought about an insertion of the zirconocene species into a benzylic carbon-oxygen bond. The oxidative insertion of Cp2Zr to the benzylic carbon-oxygen bond is a result of sequential reactions: (i) formation of zirconacyclopropane by the ligand exchange with o-(alkoxymethyl)styrene, (ii) elimination of the alkoxy group through an aromatic conjugate system giving metalated o-quinodimethane species, and (iii) transfer of zirconium metal to the benzylic position. Through use of a catalytic amount of "Cp2Zr", however, unprecedented homo-coupling reactions (dimerization) of o-(alkoxymethyl)styrene derivatives occurred to give a tetracyclic compound. On the other hand, reactions of o-(1-alkoxyisopropyl) styrene derivatives gave rise to the analogous tetracyclic compounds regardless of the amount of "Cp2Zr" (stoichiometric or catalytic). Heterocoupling product between o-(1-alkoxyisopropyl)styrene and styrene congeners was obtained in high cis stereo- and regioselectivity by treating o-(1-alkoxyisopropyl)styrene derivatives with "Cp2Zr" in the presence of an excess amount of styrene derivatives.
Oxygenated phenanthrenes via quinol ketals: Cyclization vs. migration
Morrow, Gary W.,Marks, Tina M.,Sear, Debra L.
, p. 10115 - 10124 (2007/10/02)
2-methoxyphenanthrenes were prepared by reaction of lithiated 2-bromostyrenes with quinone monoketals followed by acid-mediated cyclization of the resulting p-arylquinol ketals. Substitution at the bromostyrene side-chain or the quinone monoketal ring had only a modest effect on yields, but oxygen substitution on the bromostyrene aromatic nucleus resulted in a competing 1,2-aryl migration arising during the quinol ketal cyclization step. The extent of this rearrangement was found to be a function of the Lewis acid/solvent system employed.
