An efficient class of bis-NHC salts: applications in Pd-catalyzed reactions under mild reaction conditions

Chiu, Chien-Cheng; Chiu, Hui-Tzu; Lee, Dong‐Sheng; Lu, Ting‐Jang

doi:10.1039/c8ra04094j

Cited by 22 publications

(15 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fact is that even the coupling of 2‐bromo‐ N , N ‐dimethylaniline with phenylboronic acid is accompanied by a hydrodehalogenation process, which in some cases may become predominant . Only the use of specific catalysts and N ‐heterocyclic carbene ligands can overcome this difficulty. Another problem that arises during the reaction of sterically hindered coupling partners is hydrodeboronation .…”

Section: Resultsmentioning

confidence: 98%

Synthesis of 2‐Aryl‐ and 2,7‐Diaryl‐1,8‐bis(dimethylamino)naphthalenes. Overview of the “Buttressing effect” in 2,7‐Disubstituted Proton Sponges

et al. 2020

View full text Add to dashboard Cite

Suzuki arylation of 2‐halogeno and 2,7‐dihalogeno derivatives of 1,8‐bis(dimethylamino)naphthalene (proton sponge) was carried out. It was shown that the sterically hindered nature of the starting compounds in combination with the enhanced reactivity of their peri‐NMe2 groups allow to obtain the target 2‐aryl and 2,7‐diaryl derivatives in 20–34 % yields only. In most cases, a tandem Pd‐catalyzed hydrodehalogenation/N‐demethylation process was predominant. The latter, however, makes it possible to obtain yet unknown and synthetically valuable 2‐aryl‐N1,N1,N8‐trimethyl‐1,8‐diaminonaphthalenes (21–50 %), which can be easily converted into the corresponding proton sponges by conventional N‐methylation. Using the literature data on 2,7‐disubstituted derivatives of the proton sponge as a background together with the XRD and basicity measurements performed in this work, a comprehensive analysis of the so‐called “buttressing effect” in 2‐aryl‐ and 2,7‐diaryl‐1,8‐bis(dimethylamino)naphthalenes, along with previously unknown 2,6‐diphenyl‐N,N‐dimethyl‐p‐toluidine has been carried out for the first time.

show abstract

Section: Resultsmentioning

confidence: 98%

Synthesis of 2‐Aryl‐ and 2,7‐Diaryl‐1,8‐bis(dimethylamino)naphthalenes. Overview of the “Buttressing effect” in 2,7‐Disubstituted Proton Sponges

et al. 2020

View full text Add to dashboard Cite

show abstract

“…High-resolution mass spectra were obtained with a Finnigan/Thermo Quest MAT 95XL mass spectrometer using either the electron impact (EI) or the electrospray ionization (ESI) method. The synthesis of the bis-NHC-Ag complex was carried out according to our previous report [50].…”

Section: General Methodsmentioning

confidence: 99%

“…The NHC-ligated Pd NPs present an efficient catalytic activity in the catalysis [44][45][46][47][48]. We recently reported an in situ-generated bis-NHC/Pd(OAc)2 catalytic system, which was derived from bis-benzimidazolium salt and Pd(OAc)2, as a catalyst for the Suzuki-Miyaura reaction, Mizoroki-Heck reaction, and Friedel-Crafts alkylation reaction of indole and nitrostyrene in good to excellent yields (Figure 1a) [49,50]. Motivated by these results we continued our efforts to develop an efficient bis-NHC-Ag/Pd(OAc)2 catalytic system to catalyze chemoselective transfer hydrogenation with TEAF as a hydrogen donor (Figure 1b).…”

Section: Introductionmentioning

confidence: 99%

Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

et al. 2020

Self Cite

View full text Add to dashboard Cite

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

show abstract

“…[34] Treatment of 15 with iso-amyl nitrite in the presence of acetic acid gave the corresponding bicyclic benzotriazole 16, [35] whereas heating the same diamine in formic acid along with triethyl orthoformate at 120 °C (in a sealed tube) afforded benzimidazole 17. [36] All ester intermediates (11, 13, 16 and 17) were subjected to hydrolysis, followed by coupling of the resulting carboxylic acids with isoindoline in the presence of HATU and DIPEA to afford the desired amides (Table 1). Cleavage of the methyl ethers gave the corresponding phenols 18, 19, 20, and 21, respectively.…”

Section: Chemistrymentioning

confidence: 99%

Structure‐Based Design, Synthesis, and Biological Evaluation of Hsp90β‐Selective Inhibitors

Chaudhury

Meka

Banerjee

et al. 2021

Chemistry A European J

View full text Add to dashboard Cite

The 90 kDa heat shock proteins (Hsp90) are molecular chaperones that are responsible for the folding and/or trafficking of ~400 client proteins, many of which are directly associated with cancer progression. Consequently, inhibition of Hsp90 can exhibit similar activity as combination therapy as multiple signaling nodes can be targeted simultaneously. In fact, seventeen small-molecule inhibitors that bind the Hsp90 N-terminus entered clinical trials for the treatment of cancer, all of which exhibited pan-inhibitory activity against all four Hsp90 isoforms. Unfortunately, most demonstrated undesired effects alongside induction of the pro-survival heat shock response. As a result, isoform-selective inhibitors have been sought to overcome these detriments. Described herein is a structure-based approach to design Hsp90β-selective inhibitors along with preliminary SAR. In the end, compound 5 was shown to manifest ~370-fold selectivity for Hsp90β versus Hsp90α, and induced the degradation of select Hsp90β-dependent clients. These data support the development of Hsp90β-selective inhibitors as a new paradigm to overcome the detriments associated with pan-inhibition of Hsp90.

show abstract

An efficient class of bis-NHC salts: applications in Pd-catalyzed reactions under mild reaction conditions

Abstract: This study describes an efficient class of bis-N-heterocyclic carbene (bis-NHC) salts that can be easily made from commercially available and inexpensive starting materials.

Cited by 22 publications

References 37 publications

Synthesis of 2‐Aryl‐ and 2,7‐Diaryl‐1,8‐bis(dimethylamino)naphthalenes. Overview of the “Buttressing effect” in 2,7‐Disubstituted Proton Sponges

Synthesis of 2‐Aryl‐ and 2,7‐Diaryl‐1,8‐bis(dimethylamino)naphthalenes. Overview of the “Buttressing effect” in 2,7‐Disubstituted Proton Sponges

Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Structure‐Based Design, Synthesis, and Biological Evaluation of Hsp90β‐Selective Inhibitors

Contact Info

Product

Resources

About