7078-98-0Relevant articles and documents
Isothiourea-catalyzed enantioselective α-alkylation of esters via 1,6-conjugate addition to para-quinone methides
Arokianathar, Jude N.,Greenhalgh, Mark D.,Hartley, Will C.,McLaughlin, Calum,Ng, Sean,Slawin, Alexandra M. Z.,Smith, Andrew D.,Stead, Darren
supporting information, (2021/11/01)
The isothiourea-catalyzed enantioselective 1,6-conjugate addition of para-nitrophenyl esters to 2,6-disubstituted para-quinone methides is reported. para-Nitrophenoxide, generated in situ from initial N-acylation of the isothiourea by the para-nitrophenyl ester, is proposed to facilitate catalyst turnover in this transformation. A range of para-nitrophenyl ester products can be isolated, or derivatized in situ by addition of benzylamine to give amides at up to 99% yield. Although low diastereocontrol is observed, the diastereoisomeric ester products are separable and formed with high enantiocontrol (up to 94:6 er).
Preparation method of 4-phenyl methylene-2, 6-di-tert-butyl-2, 5-cyclohexadiene-1-ketone and derivative thereof
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Paragraph 0036-0047, (2021/05/05)
The invention provides a preparation method of 4-phenyl methylene-2, 6-di-tert-butyl-2, 5-cyclohexadiene-1-ketone and a derivative thereof, and the method comprises the following steps: reacting aromatic aldehyde, secondary amine and lewis acid in a solvent, adding a 2, 6-disubstituted phenol solution, and continuing to react to obtain a reaction solution; and washing the reaction solution and separating an organic layer to obtain the 4-phenyl methylene-2, 6-di-tert-butyl-2, 5-cyclohexadiene-1-ketone and the derivatives thereof. The method can reduce the reaction temperature, shorten the reaction time, reduce the generation of byproducts, avoid the generation of three wastes, and is green and environment-friendly.
Vinylogous Aza-Michael Addition of Urea Derivatives with p-Quinone Methides Followed by Oxidative Dearomative Cyclization: Approach to Spiroimidazolidinone Derivatives
Kaur, Navpreet,Singh, Priyanka,Banerjee, Prabal
supporting information, p. 2813 - 2824 (2021/04/21)
Herein, we report an efficient protocol for the synthesis of spiro-imidazolidinone-cyclohexadienones from p-quinone methides (p-QMs) and dialkyloxy ureas under mild conditions. The strategy follows a two-step process involving an initial vinylogous conjugate addition of urea derivatives to p-QMs, followed by oxidative dearomative cyclization of open-chain product to the projected spiro-imidazolidinones. This protocol exhibits good functional group tolerance and provides a straightforward method to access spiro-imidazolidinone-cyclohexadienones. In follow-up chemistry, we have shown the debenzylation of spiroimidazolidinones to give N-hydroxycyclic ureas. (Figure presented.).
Enantioselective Stetter Reactions Catalyzed by Bis(amino)cyclopropenylidenes: Important Role for Water as an Additive
Rezazadeh Khalkhali, Mehran,Wilde, Myron M. D.,Gravel, Michel
supporting information, p. 155 - 159 (2021/01/09)
The first highly enantioselective intermolecular Stetter reaction using simple enones is reported. A series of novel chiral BAC structures were designed and prepared. They were tested in the Stetter reaction with simple aldehydes and enones. The products were generated in excellent yields and enantioselectivities (up to 94% ee). Surprisingly, a substoichiometric amount of water was crucial to obtain high enantioselectivities. Chiral BACs were also shown to catalyze 1,6-conjugate addition reactions with paraquinone methides enantioselectively.
Metal-Free, Acid/Phosphine-Induced Regioselective Thiolation of p-Quinone Methides with Sodium Aryl/Alkyl Sulfinates
Xiong, Biquan,Xu, Shipan,Liu, Yu,Tang, Ke-Wen,Wong, Wai-Yeung
, p. 1516 - 1527 (2021/02/03)
A simple and efficient method for the regioselective thiolation of p-quinone methides with sodium aryl/alkyl sulfinates has been established using an acid/phosphine-induced radical route under transition-metal-free conditions. A broad range of sodium aryl/alkyl sulfinates and p-quinone methides (p-QMs) are compatible for the reaction, giving the expected products with good to excellent yields. Control experiments were also performed to gain insights into the generation mechanism of thiyl radicals and hydrogen-atom transfer process. This protocol provides a safe and feasible way for the formation of carbon-sulfur bonds.
Synthetic method of diaryl methyl sulfide derivatives catalyzed by organic phosphine
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Paragraph 0037; 0053-0054, (2021/07/01)
The invention provides a synthetic method of diaryl methyl sulfide derivatives catalyzed by organic phosphine. The synthetic method comprises the following steps: with tris(4-fluorophenyl)phosphorus as a catalyst and methanol as a solvent, subjecting substrates as shown in a formula I and a formula II to reacting at normal temperature for 24 hours, and carrying out column chromatography separation to obtain a product as shown in a formula III. The invention provides the synthetic method of a plurality of related new derivatives, and the substrates of the method have good universality. According to the method, tris(4-fluorophenyl)phosphorus is used as a catalyst, the substrate I and the substrate II are subjected to a thia-1,6-conjugate addition reaction, multiple diaryl methyl sulfide derivatives with uniformly distributed substituent groups are obtained, and the method is simple in process and operation process, high in product yield, mild in conditions, low in raw material cost, friendly to environment, low in energy consumption, low in equipment requirement and good in substrate applicability, has a great utilization prospect and can be applied to large-scale production by adopting a specific implementation mode.
Phosphine-Catalyzed Intermolecular Dienylation of Alkynoate with para-Quinone Methides
Song, Zefeng,Wang, Weijia,Liu, Zhixin,Lu, Yue,Wang, De
supporting information, p. 8590 - 8599 (2021/07/20)
An interesting remote I-C 1,6-Addition and an isomerization cascade reaction for phosphine-catalyzed activated alkynes have been disclosed. The products featuring a functional diene and a 1,1-diaryl methyl motif have been obtained in moderate to good yields (30-86%) by applying para-quinone methides (p-QMs) and I-substituted alkynoate with tributylphosphine (PnBu3) catalysis, along with high regioselectivity and stereoselectivity (dr > 20:1). The wide scope of compatible substrates (35 examples), such as indolyl, oxindolyl, ester, and cinnamyl, expand the utility of this methodology. A plausible mechanism and some applications of it have also been presented.
Thiourea catalyzed 1,6-conjugate addition of indoles to para-quinone methides
Wu, Guangmiao,Li, Tao,Liu, Fuhai,Zhao, Yulong,Ma, Shiqiang,Tang, Shouchu,Xie, Xingang,She, Xuegong
supporting information, (2021/09/09)
An efficient thiourea catalyzed 1,6-conjugate addition of indoles to para-quinone methides (p-QMs) was developed. p-QMs was activated by a weak hydrogen-bond effect. The reaction is featured mild reaction conditions and wide substrate scope. A series of C-3 bisaryl methine substituted indoles are prepared in high yield.
Metal-free, Tf2NH-catalyzed 1, 6-conjugate addition of imidazopyridine to para-quinone methides: Easy access to C3-functionalized triarylmethane imidazopyridine
Khonde, Nilesh S.,Said, Madhukar S.,Sabane, Jagjivan K.,Gajbhiye, Jayant M.,Kumar, Pradeep
supporting information, (2021/10/30)
An inexpensive and commercially available Tf2NH-catalyzed 1,6-conjugate addition of imidazopyridine (IMPY) heterocycles to para-quinone methides (p-QMs) is reported. The present transformation provides a diverse class of C3-functionalized triarylmethanes heterocyclic derivatives of imidazopyridine. These metal-free transformations provided a very broad substrate scope of conjugate addition product with a high yield up to 97% within a short duration.
Silver-Catalyzed Regioselective Phosphorylation of para-Quinone Methides with P(III)-Nucleophiles
Liu, Yu,Tang, Ke-Wen,Wong, Wai-Yeung,Xie, Jun,Xiong, Biquan,Xu, Shipan,Xu, Weifeng
, p. 14983 - 15003 (2021/11/12)
A simple and efficient method for the silver-catalyzed regioselective phosphorylation of para-quinone methides (p-QMs) with P(III)-nucleophiles (P(OR)3, ArP(OR)2, Ar2P-OR) has been established via Michaelis-Arbuzov-type reaction. A broad range of P(III)-nucleophiles and para-quinone methides are well tolerated under the mild conditions, giving the expected diarylmethyl-substituted organophosphorus compounds with good to excellent yields. Moreover, a series of corresponding enantiomers can be obtained by employing dialkyl arylphosphonite (ArP(OR)2) as substrates. The control experiments and 31P NMR tracking experiments were also performed to gain insights for the plausible reaction mechanism. This protocol may have significant implications for the formation of C(sp3)-P bonds in Michaelis-Arbuzov-type reactions.
