41772-31-0Relevant academic research and scientific papers
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).
Towards ortho-selective electrophilic substitution/addition to phenolates in anhydrous solvents
Lopu?anskaja, Eleana,Kooli, Anni,Paju, Anne,J?rving, Ivar,Lopp, Margus
, (2021/02/16)
Alkyl-substituted Li-phenolates with BnBr in water solution lead to a mixture of o- and p-Bn-substituted phenols together with a substantial amount of phenol Bn ether. In CPME, and especially in toluene with 1–2 equivalents of ether or alcohol additives, ortho-selective alkylation is achieved. In the case of o,o,p-tri- and o,o-di-substituted phenols dearomatization occurs affording o-Bn-substituted alkyl cyclohexadienones with yields up to 92% with an o/p ratio up to 90/1.
Uranyl-catalyzed hydrosilylation ofpara-quinone methides: access to diarylmethane derivatives
Yu, Jipan,Chen, Siyu,Liu, Kang,Yuan, Liyong,Mei, Lei,Chai, Zhifang,Shi, Weiqun
supporting information, p. 1575 - 1579 (2021/03/01)
An efficient and convenient uranyl-catalyzed reductive hydrosilylation reaction ofpara-quinone methides (p-QMs) was developed by employing silane as the reductant. The hydrosilylation procedure using the UO2(NO3)2·6H2
TBAB-catalyzed 1,6-conjugate sulfonylation of paraquinone methides: A highly efficient approach to unsymmetrical gem-diarylmethyl sulfones in water ?
Liu, Zhang-Qin,You, Peng-Sheng,Zhang, Liang-Dong,Liu, Da-Qing,Liu, Sheng-Shu,Guan, Xiao-Yu
supporting information, (2020/02/11)
A highly efficient sulfonylation of para-quinone methides with sulfonyl hydrazines in water has been developed on the basis of the mode involving a tetrabutyl ammonium bromide (TBAB)-promoted sulfa-1,6-conjugated addition pathway. This reaction provides a green and sustainable method to synthesize various unsymmetrical diarylmethyl sulfones, showing good functional group tolerance, scalability, and regioselectivity. Further transformation of the resulting diarylmethyl sulfones provides an efficient route to some functionalized molecules.
Site-selective Oxidative Dearomatization of Phenols and Naphthols into ortho-Quinols or Epoxy ortho-Quinols using Oxone as the Source of Dimethyldioxirane
Cabrera-Afonso, María J.,Carre?o, M. Carmen,Urbano, Antonio
supporting information, (2019/08/21)
A novel reactivity of dimethyldioxirane, generated in situ from Oxone and acetone, with substituted phenols and naphthols is reported. This methodology allowed the synthesis of ortho-quinols or epoxy ortho-quinols from a site-selective oxidative dearomatization process, with good yields under very mild conditions. A short total synthesis of natural product lacinilene C methyl ether is also described using this process as the key step. (Figure presented.).
Enantioselective Spirocyclopropanation of para-Quinone Methides Using Ammonium Ylides
Roiser, Lukas,Waser, Mario
supporting information, p. 2338 - 2341 (2017/05/12)
The use of Cinchona alkaloid-based chiral ammonium ylides allows for the first highly enantioselective and broadly applicable spirocyclopropanation reactions of para-quinone methides. This strategy provides a straightforward protocol toward the chiral spiro[2.5]octa-4,7-dien-6-one skeleton, which is a frequently found structural motif in important biologically active molecules.
B(C6F5)3 catalysed reduction of: Para -quinone methides and fuchsones to access unsymmetrical diaryl- and triarylmethanes: Elaboration to beclobrate
Mahesh, Sriram,Vijaya Anand, Ramasamy
, p. 8393 - 8401 (2017/10/19)
A mild and efficient method for the synthesis of unsymmetrical diaryl- and triarylmethanes through a B(C6F5)3 catalyzed reduction of para-quinone methides and fuchsones respectively, using the Hantzsch ester as a reducing source has been developed. Detailed mechanistic investigations revealed that the reaction actually proceeds through a Lewis acid-base pair complex derived from B(C6F5)3 and the Hantzsch ester.
1,6-Addition Arylation of para-Quinone Methides: An Approach to Unsymmetrical Triarylmethanes
Gao, Shang,Xu, Xiuyan,Yuan, Zhenbo,Zhou, Haipin,Yao, Hequan,Lin, Aijun
supporting information, p. 3006 - 3012 (2016/07/11)
A 1,6-addition arylation reaction of para-quinone methides with α-isocyanoacetamides and electron-rich aromatic compounds under metal-free conditions has been developed. BF3·Et2O plays two roles in the reaction: catalyzing the cyclization of α-isocyanoacetamides to give oxazoles, and activating the para-quinone methides to achieve the 1,6-addition arylation process. The reaction shows good functional group tolerance, scalability, and regioselectivity. It is a consice protocol for the synthesis of diverse unsymmetrical triarylmethanes. Further transformation of the resulting triarylmethanes provides an efficient route to some functionalized molecules.
Copper-catalyzed silylation of p-quinone methides: New entry to dibenzylic silanes
López, Aurora,Parra, Alejandro,Jarava-Barrera, Carlos,Tortosa, Mariola
supporting information, p. 17684 - 17687 (2015/12/18)
An efficient and general copper(i)-catalyzed silylation of p-quinone-methides is described. Non-symmetric dibenzylic silanes are obtained in high yields under mild reaction conditions. These compounds can be used as bench-stable benzylic carbanion precursors.
Synthesis of spiro[2.5]octa-4,7-dien-6-one with consecutive quaternary centers via 1,6-conjugate addition induced dearomatization of para-quinone methides
Gai, Kuo,Fang, Xinxin,Li, Xuanyi,Xu, Jinyi,Wu, Xiaoming,Lin, Aijun,Yao, Hequan
supporting information, p. 15831 - 15834 (2015/11/10)
An efficient one-pot approach for the synthesis of spiro[2.5]octa-4,7-dien-6-ones by employing para-quinone methides has been developed. The reaction proceeded smoothly in high yields under mild conditions without the use of metals. Moreover, all products obtained herein contained two or three consecutive quaternary centers.
