764-01-2Relevant articles and documents
BiCl3-Facilitated removal of methoxymethyl-ether/ester derivatives and DFT study of -O-C-O- bond cleavage
Pacherille, Angela,Tuga, Beza,Hallooman, Dhanashree,Dos Reis, Isaac,Vermette, Mélodie,Issack, Bilkiss B.,Rhyman, Lydia,Ramasami, Ponnadurai,Sunasee, Rajesh
supporting information, p. 7109 - 7116 (2021/05/03)
A simple method for the cleavage of methoxymethyl (MOM)-ether and ester derivatives using bismuth trichloride (BiCl3) is described. The alkyl, alkenyl, alkynyl, benzyl and anthracene MOM ether derivatives, as well as MOM esters of both aliphatic and aromatic carboxylic acids, were deprotected in good yields. To better understand the molecular roles of BiCl3and water for MOM cleavage, two possible binding pathways were investigated using the density functional theory (DFT) method. The theoretical results indicate the differential initial binding site preferences of phenolic and alcoholic MOM substrates to the Bi atom and suggest that water plays a key role in facilitating the cleavage of the MOM group.
Synthesis and Photoswitching Properties of Bioinspired Dissymmetric I-Pyrone, an Analogue of Cyclocurcumin
Pecourneau, Jérémy,Losantos, Raúl,Monari, Antonio,Parant, Stéphane,Pasc, Andreea,Mourer, Maxime
, p. 8112 - 8126 (2021/06/30)
Cyclocurcumin (CC), a turmeric curcuminoid with potential therapeutic properties, is also a natural photoswitch that may undergo E/Z photoisomerization under UV light. To be further exploited in relevant biological applications, photoactivation under near-infrared (NIR) irradiation is required. Such requirement can be met through opportune chemical modifications, by favoring two-photon absorption (TPA) probability. Herein, a general and efficient synthesis of a biomimetic 2,6-disubstituted-δ-pyrone analogue of CC is described, motivated by the fact that molecular modeling previews an order of magnitude increase of its NIR TPA compared to CC. Three retrosynthetic pathways have been identified (i) via an aryl-oxazole intermediate or via aryl-diynone through (ii) a bottom-up or (iii) a top-down approach. While avoiding the passage through unstable synthons or low-yield intermediate reactions, only the latest approach could conveniently afford the 2,6-disubstituted-I-pyrone analogue of CC, in ten steps and with an overall yield of 18%. The photophysical properties of our biomimetic analogue have also been characterized showing an improved photoisomerization yield over the parent natural compound. The potentially improved nonlinear optical properties, as well as enhanced stability, may be correlated to the enforcement of the planarity of the pyrone moiety leading to a quadrupolar D-π-A-π-D system.
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
Shi, Taoda,Teng, Shenghan,Gopi Krishna Reddy, Alavala,Guo, Xin,Zhang, Yueteng,Moore, Kohlson T.,Buckley, Thomas,Mason, Damian J.,Wang, Wei,Chapman, Eli,Hu, Wenhao
supporting information, p. 8737 - 8744 (2019/10/16)
We report a bifunctional Ag catalyst promoted intramolecular capture of oxonium ylides with alkynes for the enantioselective synthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with respect to 9, suggesting that two molecules of 9 are involved in the intramolecular trapping of a Ag-associated oxonium ylide with a Ag-activated alkyne. Based on our mechanistic hypothesis, we further optimized the reaction, rendering a facile approach to 2,5-dihydrofurans in good to excellent yields in a highly chemo- and enantioselective fashion.
Nickel(II)-Catalyzed Asymmetric Propargyl [2,3] Wittig Rearrangement of Oxindole Derivatives: A Chiral Amplification Effect
Xu, Xi,Zhang, Jianlin,Dong, Shunxi,Lin, Lili,Lin, Xiaobin,Liu, Xiaohua,Feng, Xiaoming
supporting information, p. 8734 - 8738 (2018/07/14)
A highly enantioselective [2,3] Wittig rearrangement of oxindole derivatives was realized by using a chiral N,N′-dioxide/NiII complex as the catalyst under mild reaction conditions. A strong chiral amplification effect was observed, and allowed access to chiral 3-hydroxy 3-substituted oxindoles bearing allenyl groups in high yields and enantioselectivities (up to 92 % ee) by using a ligand with only 15 % ee. A reasonable explanation was given based on the experimental investigations and X-ray crystal structures of enantiomerically pure and racemic catalysts. Moreover, the first catalytic kinetic resolution of racemic oxindole derivatives by a [2,3] Wittig rearrangement was realized with high efficiency and stereoselectivity.
Electrochemical Deprotection of para-Methoxybenzyl Ethers in a Flow Electrolysis Cell
Green, Robert A.,Jolley, Katherine E.,Al-Hadedi, Azzam A. M.,Pletcher, Derek,Harrowven, David C.,De Frutos, Oscar,Mateos, Carlos,Klauber, David J.,Rincón, Juan A.,Brown, Richard C. D.
supporting information, p. 2050 - 2053 (2017/04/27)
Electrochemical deprotection of p-methoxybenzyl (PMB) ethers was performed in an undivided electrochemical flow reactor in MeOH solution, leading to the unmasked alcohol and p-methoxybenzaldehyde dimethyl acetal as a byproduct. The electrochemical method removes the need for chemical oxidants, and added electrolyte (BF4NEt4) can be recovered and reused. The method was applied to 17 substrates with high conversions in a single pass, yields up to 92%, and up to 7.5 g h-1 productivity. The PMB protecting group was also selectively removed in the presence of some other common alcohol protecting groups.
A 1 - bromo - 2 - ethyl-acetylene production method (by machine translation)
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Paragraph 0014, (2017/06/13)
The invention relates to a 1 - bromo - 2 - ethyl-acetylene production method, including in the THF bromoethane with magnesium metal in the reaction to prepare the Grignard reagent, then to the Grignard reagent in the form after adding poly-formaldehyde reaction, format after the reaction separation and recovery 2 - ethyl-acetylene - 1 - ol; and will 2 - ethyl-acetylene - 1 - ol with phosphorus tribromide bromination reaction, bromination reaction after the end of the separation and recovery of 1 - bromo - 2 - ethyl-acetylene. In this invention the format adopted for the more common reaction currently in use, and does not need special production equipment, the reaction condition is comparatively mild, in industrialized production process is more stable, with a low risk. The phosphorus tribromide to 2 - ethyl-acetylene - 1 - ol performing the bromination, the utilization rate of high, produce by-products phosphoric acid and in pyridine and easy processing. (by machine translation)
A kind of 2-butyne-1-ol synthesis method
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Paragraph 0030-0035, (2017/02/24)
The invention discloses a synthetic method for 2-butyne-1-ol. Innovation points of the invention are as follows: a waste liquid containing 1,3-dichloro-2-butylene and produced in rubber production is used as a starting raw material and undergoes hydrolysis so as to obtain 3-chloro-2-butenyl-1-ol, then elimination is carried out so as to obtain 2-butyne-1-ol, and finally high-purity 2-butyne-1-ol is prepared. According to the synthetic method for 2-butyne-1-ol, the raw material is the waste liquid produced in rubber production and is cheap and widely available, so utilization of the waste, greenness and environmental protection are realized. The synthetic method is simple and is safe and easy to operate; and consumed labor force and resources by the method are substantially reduced. Product yield reaches more than 88%, and product purity reaches 96 to 98%.
Stereoselective synthesis of the KJ ring system of yessotoxin by Pd(II)-catalyzed cyclization
Yokoyama, Hajime,Nishida, Kazuki,Togawa, Takashi,Yamagami, Masaki,Miyazawa, Masahiro,Hirai, Yoshiro
, p. 4379 - 4381 (2016/09/13)
Yessotoxin was isolated from the digestive glands of the scallop, Patinopecten yessoensis, and would be of use as a promising therapeutic tool. We attained the stereoselective construction of KJ ring system of yessotoxin by the intramolecular cyclization of the trisubstituted allylic alcohol using Pd(II) catalyst.
Benzannulation of triynes to generate functionalized arenes by spontaneous incorporation of nucleophiles
Karmakar, Rajdip,Yun, Sang Young,Chen, Jiajia,Xia, Yuanzhi,Lee, Daesung
supporting information, p. 6582 - 6586 (2015/06/02)
The thermal reaction of ester-tethered 1,3,8-triynes provides novel benzannulation products with concomitant incorporation of a nucleophile. Evidence suggests that this reaction proceeds via an allene-enyne intermediate generated by an Alder-ene reaction in the first step. Depending on the substituent of the alkyne moiety on the allene-enyne intermediate, the subsequent transformation can take one of two different paths, each leading to discrete aromatization products. The benzannulation of a silane-substituted 1,3,8-triynes provides arene products with a nucleophile incorporated onto the newly formed benzene core, whereas an aryl substituent leads to nucleophile trapping at the benzylic carbon atom connected to the aryl substituent. The formation of these two different products results from the involvement of two regioisomeric allene-enyne intermediates.
Highly enantioselective nickel-catalyzed intramolecular reductive cyclization of alkynones
Fu, Wenzhen,Nie, Ming,Wang, Aizhen,Cao, Ziping,Tang, Wenjun
supporting information, p. 2520 - 2524 (2015/03/04)
The first asymmetric nickel-catalyzed intramolecular reductive cyclization of alkynones is reported. A P-chiral monophosphine and triethylsilane were used as the ligand and the reducing reagent, respectively, to form a series of tertiary allylic alcohols bearing furan/pyran rings in excellent yields and enantioselectivities. This reaction has a broad substrate scope and enabled the efficient synthesis of dehydroxycubebin and chiral dibenzocyclooctadiene skeletons.
