Haohua Chen's research while affiliated with Chongqing University and other places

Publications (31)

Article
Bicyclo[1.1.0]butane (BCB) derivatives are versatile coupling partners, and various reaction modes for their activation and transformation have been proposed. In this work, three BCB-activation modes in Rh-catalyzed BCB transformations that construct diastereoselective α-quaternary β-lactones were investigated by density functional theory calculati...
Article
Axially chiral open‐chain olefins represent an underexplored class of chiral platform. In this report, two classes of tetrasubstituted axially chiral acyclic olefins have been accessed in excellent enantioselectivity and regioselectivity via C‐H activation of (hetero)arenes assisted by a migratable directing group en route to coupling with sterical...
Article
Axially chiral open‐chain olefins represent an underexplored class of chiral platform. In this report, two classes of tetrasubstituted axially chiral acyclic olefins have been accessed in excellent enantioselectivity and regioselectivity via C‐H activation of (hetero)arenes assisted by a migratable directing group en route to coupling with sterical...
Article
Enynones are powerful synthons for constructing furan derivatives in the presence of transition metal catalysts. Unlike the conventional intramolecular nucleophilic attack with the activation of coinage metals, we propose that enynones undergo an oxidative cyclization process with a Pd(0) species. The full catalytic cycle involves oxidative cycliza...
Article
In this report, distally disposed axial and central chirality has been installed in a synergistic fashion via rhodium-catalyzed C-H alkylation of benzamides using N-arylmaleimide as the alkylating reagent, in which the enantio- and diastereo-determining steps are merged into a single one. The coupling system features mild reaction conditions, broad...
Article
Over the past few decades, platinum has attracted remarkable attention and played an important role in promoting construction of C–X (X = C, O, N, B, etc.) bonds in organometallic chemistry. However, understanding the general principle of Pt chemistry is still an urgent task both experimentally and theoretically. Differing from other metals in the...
Article
Inspired by the body circulation of Omeprazole (irreversible proton pump inhibitor), we disclose the carbene-triggered cascades for the synthesis of 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing thiocarbamates, which represents an unprecedented imine derivative migration process. Furthermore, the desulfuriz...
Article
Control of regioselectivity that defies the intrinsic reactivity of arene C-H bonds remains a formidable challenge. In this work, dimeric Rh(II) complexes have been applied as an efficient catalyst for the regioselective coupling of NH indoles with diazo compounds. Two-substituted indoles mostly reacted with C(6) selectivity. Mechanistic studies re...
Article
Full-text available
[2,3]-Sigmatropic rearrangement of ammonium ylides represents a fundamental reaction for stereoselective synthesis of nitrogenous compounds. However, its applicability is limited by the scarcity of efficient, catalytic, and mild methods for generating ammonium ylides. Here, we report silver-catalyzed domino generation/[2,3]-sigmatropic rearrangemen...
Article
Full-text available
A visible-light-driven oxidative 6π heterocycilization for the synthesis of structurally diverse π-conjugated polycyclic 1-aminoisoquinolines has been developed. The reaction proceeds under visible-light or sunshine, obviates photocatalyst and transition-metals, and features...
Article
Divergent synthesis for precise constructions of cyclic unsymmetrical diaryl disulfides or diselenides and polythiophenes from CF 3 -containing 1,3-enynes and S 8 was developed when the ortho group is F, Cl, Br and NO 2 on aromatic rings. Meanwhile, disulfides (diselenides) were also quickly constructed when the ortho group is H. These transformati...
Article
A divergent synthesis for construction of cyclic unsymmetrical diaryl disulfides, diselenides, and polythiophenes from CF3‐containing 1,3‐enynes (ortho=F, Cl, Br, NO2, S8) was developed. Disulfides (diselenides) were constructed under mild conditions for ortho=H. These transformations undergo a cascade thiophene construction/selective C3‐position t...
Article
CF3-containing multi-borylated compounds are intriguing molecules that can serve as building blocks and readily transform into various significant molecules. Here, a series of Cu-catalyzed assembly of 1,3- and 1,4-diborylated compounds bearing CF3 group starting from readily available 1,3-enynes has been developed. This is the first example that co...
Article
Ir catalysis is widely used in hydrogenation reactions to transform unsaturated molecules to the corresponding saturated molecules. Understanding the reaction mechanism is helpful for design of new Ir-catalyzed hydrogenation reactions, as well as for controlling the regio/stereoselectivity. Density functional theory is a powerful tool for mechanist...
Article
Full-text available
Acyclic contiguous stereocenters are frequently seen in biologically active natural and synthetic molecules. Although various synthetic methods have been reported, predictable and unified approaches to all possible stereoisomers are rare, particularly for those containing non-reactive hydrocarbon substituents. Herein, a β-boronyl group is employed...
Article
The Rh(III)-catalyzed reactions of α,β-unsaturated oximes with alkenes are versatile methods for the synthesis of pyri-dines. Density functional theory (DFT) calculations reported here reveal the detailed mechanism and origins of selec-tivity in this reaction. The Rh(III)/Rh(V)/Rh(I) catalytic cycle was found to be more favorable than the previousl...
Article
Palladium‐catalyzed transformation reactions of unsaturated molecules have considerable importance because of their versatility and wide range of applications. Over the past decades, various experimental studies on palladium‐catalyzed unsaturated bond transformation have been reported, and mechanistic and computational studies have also progressed...
Article
Full-text available
An unprecedented S8-catalyzed selective triple-cleavage of bromodifluoroacetamides is disclosed for the first time. Valuable 2-amido substituted benzimidazoles, benzoxazoles as well as benzothiazoles were obtained in good to excellent yields in a cascade protocol in this strategy. The mechanistic studies suggested that a C2 source was generated in...
Article
Alkaline-earth (Ae) metals have attracted a wealth of interdependent research from synthetic chemists. In Ae-catalyzed organometallic reactions, β-diketiminate is a typical ligand used to stabilize Ae catalysts by forming six-membered rings comprising Ae metals. Herein, studies focusing on the configuration of β-diketiminate-coordinated Ae compound...
Article
DFT calculations are used to reveal the mechanism of Brønsted-base-mediated borylation of propynols. The reaction is predicted to go through a key intermediate of alkenylboronate. Therefore, the possible pathways involve two key steps, borylation and reductive dehydroxylation. The favored pathway for the generation of the alkenylboronate intermedia...
Article
Full-text available
Density functional theory (DFT) calculations have been performed to investigate the mechanism of alkaline-earth-metal-catalyzed hydroboration of pyridines with borane. In this reaction, the active catalytic species is considered to be an alkaline earth metal hydride complex when the corresponding alkaline earth metal is used as the catalyst. The th...
Article
Reported herein is the first organocatalytic asymmetric C(sp3)–H functionalization of biomass-derived 2,5-dimethylfuran with alcohols to afford enantioenriched furan-derived 3,3-disubstituted oxindoles in high enantioselectivity. This reaction is realized through chiral acid-catalyzed two sequential Cope-type rearrangements as proved by DFT calcul...
Article
An efficient method for preparing highly functionalized chiral nonspiro-phosphonylpyrazolines via an asymmetric formal 1,3-dipolar cycloaddition reaction of α-diazomethylphosphonate with activated, acyclic α,β-unsaturated ketones, bearing an additional nitrile electron-withdrawing group, has been developed, utilizing an in situ generated chiral sil...
Article
A novel chiral phosphine–urea bifunctional ligand has been developed for Cu-catalyzed asymmetric 1,3-dipolar cycloaddition of iminoesters with methacrylonitrile, a long-standing challenging substrate in asymmetric catalysis. Distortion–interaction energy analysis based on density functional theory (DFT) calculations reveals that the distortion ener...
Article
An efficient approach to tetrasubstituted alkenylboronates via a cascade borylation/B–O elimination of propynols and B2pin2 was disclosed. A series of tetrasubstituted alkenylboronates were readily furnished with this strategy in good yields, with further transformations leading to tetrasubstituted alkenes and β-diketones demonstrating the syntheti...
Article
Phosphoric acid catalysis is a powerful tool for the construction of new CC bonds because of its unique LUMO-lowering activity. Theoretical calculations were employed to investigate phosphoric acid-catalyzed asymmetric conjugate addition of indolizines to α,β-unsaturated ketones. The calculation results showed that this transformation proceeds via...

Citations

... and axially chiral open-chain olefins have also been constructed. [77][78][79] In contrast, asymmetric hydrofunctionalization of alkynes that affords trisubstituted axially chiral olefins remains underexplored. This is likely ascribed to the intrinsically low reactivity of sterically hindered alkynes and low atropostability of trisubstituted olefins. ...
... Indeed, the metal tends to end up at the vinyl site that is distal to the bulky aryl group on the basis of our previous studies. [32][33][34] Protonolysis of the C-Pd bond eventually furnished the coupled product. In the enantio-determining migratory insertion, the more hindered indole moiety of the alkyne tends to be placed downward and two orientations (E and E' shown in Fig. 7) of the alkyne versus the PPh 2 group can be visioned. ...
... The further oxidative transformations were successfully achieved by utilizing DDQ as oxidant, leading to the formation of fascinating 2H-pyrrole 113a and poly-substituted pyrrole 113b, respectively. More recen tly, Li and coworkers successfully created N-aryl succinimides 119, containing an axially chiral axis and a central chirality via a single stereo-determining step, in which the rhodium-catalyzed C-H alkylation of benzamides 117 was utilized, with N-arylmaleimides 118 as the alkylating rea gent (Scheme 28) [90]. This transformation featured mild reaction conditions, broad functional group tolerance, and excellent enantio-and diastereo-selectivity. ...
... Given the size of the N-phthalimido and adamantyl ligands on Rh 2 (R-PTAD) 4 (weighing in at 219 atoms and 940 electrons), and the concomitant computational cost, we reasoned that truncating the adamantyl groups to methyl groups struck a sensible balance between mechanistic insight and cost with the modeling capabilities at our disposal. 23,24 A stepwise mechanism involving a short lived zwitterionic intermediate was found for the reactions of substrate 2, similar to that previously proposed for C-H insertions of donor/donor carbenes with primary, achiral insertion sites 7 (see computational ESI † for details; all computed structures can be found in the ioChem-BD repository 25 ). For clarity, the mechanism for formation of one enantiomer of the major diastereomer from diazo compound 7 is shown in Fig. 4 (see ESI Fig. 4-5 † for detailed reaction proles for formation of the other diastereomer and its enantiomer). ...
... Both hydroboration and diboration are well established for alkenes/alkynes 20−25 and also for more challenging allenes, 26−28 1,3-dienes, 29−32 and 1,3-enynes functionalization. 33 −35 In contrast to this, the addition of boryl group(s) to 1,3-diynes is practically unexplored. The reason for this is possible overreduction, formation of a mixture of various products and their isomers, and problems in selective activation of the one C�C bond, which often requires the application of precisely designed metal complexes. ...
... It was suggested that N-M′ functionality is not necessarily cleaved or formed during the catalytic cycle, but instead stabilizes the rate-determining transition states via non-covalent interactions (Fig. 1c, X = M′) 27,[30][31][32]37 . Although this important postulated mechanism is supported by theoretical calculation studies 27,[30][31][32]38,39 , a lack of compelling experimental evidence remains a concern. In particular, the isolation of the key intermediate, highly reactive HM-NM′ species, is a major challenge [35][36][37] . ...
... The intramolecular coordination between enolate oxygen and benzylic boron in int IV-a could set a nearly planar five-membered ring and the following α-protonation should preferentially come from the less hindered side, thus leading to syn-diastereomer 2a. [18] In path B, conjugate borylation, syn-protonation might take place prior to alkyne borylation. Although not conclusive, we propose that path A is more likely than path B since, on the one hand, α-substitution and cross-conjugation of 1a might retard the ...
... The NBO charges [42] and Wiberg bond indices were obtained at the B3LYP/BSI level. The reliability of the M06-2X//B3LYP combination is demonstrated by its effective use in addressing various transition metal catalytic reactions [43][44][45][46][47][48][49][50][51][52]. The total energy of all the optimized structures are shown in Table S1. ...
... In recent years, S 8 has received extensive attention in chemical synthesis due to its availability, non-toxicity, ease of execution, stability as well as the ability to give rise to myriads of fascinating and intriguing transformations [19][20][21][22][23][24] . Besides, elemental sulfur could be employed as effective catalyst to promote a plethora of transformations as well [25][26] . Therefore, S 8 as sulfur source used in monothiooxamides is the best chioce [27][28][29] . ...
... As an example (Scheme 1b), amines often act as typical nucleophiles to achieve hydroamination through the formal insertion of an unsaturated molecule into an N -H bond [44][45][46][47][48]. However, in the presence of a nickel catalyst, an alternative hydroaminomethylation was observed, which can be considered to be the insertion of an alkyne into a relatively inactive aliphatic C-H bond [49][50][51][52][53]. On the basis of previous experimental observations, a key intermediate for this reaction is considered to be an imine species, which can be afforded by the formal dehydrogenation of the corresponding amine [54][55][56][57]. ...