- Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
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A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
- Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
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supporting information
p. 6007 - 6014
(2019/06/24)
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- Diaryl hydroxylamines as pan or dual inhibitors of indoleamine 2,3-dioxygenase-1, indoleamine 2,3-dioxygenase-2 and tryptophan dioxygenase
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Tryptophan (Trp) catabolizing enzymes play an important and complex role in the development of cancer. Significant evidence implicates them in a range of inflammatory and immunosuppressive activities. Whereas inhibitors of indoleamine 2,3-dioxygenase-1 (IDO1) have been reported and analyzed in the clinic, fewer inhibitors have been described for tryptophan dioxygenase (TDO) and indoleamine 2,3-dioxygenase-2 (IDO2) which also have been implicated more recently in cancer, inflammation and immune control. Consequently the development of dual or pan inhibitors of these Trp catabolizing enzymes may represent a therapeutically important area of research. This is the first report to describe the development of dual and pan inhibitors of IDO1, TDO and IDO2.
- Winters, Maria,DuHadaway, James B.,Pham, Khoa N.,Lewis-Ballester, Ariel,Badir, Shorouk,Wai, Jenny,Sheikh, Eesha,Yeh, Syun-Ru,Prendergast, George C.,Muller, Alexander J.,Malachowski, William P.
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supporting information
p. 455 - 464
(2018/11/25)
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- Selective Late-Stage Hydrodefluorination of Trifluoromethylarenes: A Facile Access to Difluoromethylarenes
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A selective reductive monodefluorination reaction of trifluoromethyl arenes was developed. Mediated by magnesium metal, various difluoromethylated aromatics were accessed at room temperature in the presence of acetic acid. This protocol shows tolerance to a wide range of functional groups and it was applicable in late-stage hydrodefluorination of complex pharmaceutical compounds, affording the corresponding CF2H analogues and their deuterated (CF2D) counterparts.
- Munoz, Socrates B.,Ni, Chuanfa,Zhang, Zhe,Wang, Fang,Shao, Nan,Mathew, Thomas,Olah, George A.,Prakash, G. K. Surya
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supporting information
p. 2322 - 2326
(2017/05/01)
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- Direct allylation of benzyl alcohols, diarylmethanols, and triarylmethanols mediated by XtalFluor-E
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We report the direct allylation of benzyl alcohols, diarylmethanols and triarylmethanols mediated by XtalFluor-E using allyltrimethylsilane. The resulting allylated products are obtained in moderate to high yield.
- Lebleu, Thomas,Paquin, Jean-Fran?ois
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supporting information
p. 442 - 444
(2017/01/10)
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- FeCl3-catalyzed 1,2-addition reactions of aryl aldehydes with arylboronic acids
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(Chemical Equation Presented) A novel protocol for the 1,2-addition reactions of electron-deficient aryl aldehydes with arylboronic acids using an inexpensive and environmentally benign iron catalyst is reported. In the presence of FeCl3 and 2-
- Zou, Tao,Pi, Sha-Sha,Li, Jin-Heng
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supporting information; experimental part
p. 453 - 456
(2009/07/11)
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- A new route to acyclic diaminocarbenes via lithium-halogen exchange
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A lithium - halogen exchange route has been developed to generate acyclic diaminocarbenes (ADC) from chloroamidinium salts. Convenient access to various ADC complexes (B, Rh, lr, Pd) stems from a one-pot transmetalation protocol. Formation of a carbenoid species is suggested by 1D and 2D NMR studies with a 13C-labeled chloroamidinium precursor and also by X-ray structures of transition metal-carbene complexes. Rh-ADC complex 4 is an effective catalyst for the 1,2-addition of aryl boronic acids to aryl aldehydes.
- Snead, David R.,Ghiviriga, Ion,Abboud, Khalil A.,Hong, Sukwon
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supporting information; experimental part
p. 3274 - 3277
(2009/12/01)
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- Thiourea inhibitors of herpes viruses. Part 2: N-Benzyl-N′- arylthiourea inhibitors of CMV
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A series of highly potent thiourea inhibitors of cytomegalovirus (CMV) with improved stability properties was prepared and evaluated. Compound 29 inhibited the virus in cultured HFF cells with IC50 of 0.2nM.
- Bloom, Jonathan D.,Dushin, Russell G.,Curran, Kevin J.,Donahue, Fran,Norton, Emily B.,Terefenko, Eugene,Jones, Thomas R.,Ross, Adma A.,Feld, Boris,Lang, Stanley A.,DiGrandi, Martin J.
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p. 3401 - 3406
(2007/10/03)
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