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Indium(III) triflate was found to be an efficient metal catalyst for the electrophilic substitution reaction of substituted indoles with various isatins or aryl aldehydes in acetonitrile solvent to afford the corresponding 3,3-diaryloxindoles or bis(indol-3-yl)methanes, respectively, in high yields at room temperature. This new procedure has remarkable features such as experimental simplicity, high conversions, good to excellent yields, short reaction times, and simple workup procedures

The selective construction of two C(sp³)–C(sp³) bonds through trimolecular cross-coupling of unactivated alkenes remains one of the most difficult challenges in organic synthesis. Despite previous advances in metal-catalyzed coupling for the dicarbofunctionalization of alkenes, dialkylation is still problematic due to the instability of the requisite metal–alkyl intermediate, which undergoes facile β-hydride elimination or protodemetalation. Recently, our group was successful in developing a bimolecular homolytic substitution (S_H2) strategy that circumvents metal–alkyl side reactions and accomplishes the challenging cross-coupling of metal–alkyl intermediates with alkyl radicals in the absence of a directing auxiliary, permitting a highly regioselective dialkylation of unactivated alkenes.

1 Introduction

2 Nickel-Catalyzed Dicarbofunctionalization of Unactivated Alkenes

3 Nickel-Catalyzed Dialkylation of Unactivated Alkenes

4 Conclusions and Perspectives

We report a practical scalable synthesis of the natural product (±)-tylophorine by using an operationally simple protecting-group-free route from readily accessible starting materials. Synthesis of a cyclic N-acetyl diester compound through cyclization, followed by two key steps (decarboxylation and a Clemmensen reduction), provides access to the target molecule.

Carbohydrates and their conjugates play important roles in life activities and drug development. Our group was committed to the general and effective glycosylation methods and their application in chemical biology using unsaturated glycosyl donors. In the past five years, we have reported several synthetic strategies with high stereoselectivity and milder conditions compared with previous works. In particular, high chemo-/regio- and stereoselective O-glycosylation, C-glycosylation and S-glycosylation could be achieved via palladium catalysis under open-air conditions at room temperature. In this Account, we will introduce our research progress in constructing four types of glycosides.

1 Introduction

2 Stereoselective Synthesis of O-Glycosides

3 Stereoselective Synthesis of C-Glycosides

4 Stereoselective Synthesis of N-Glycosides

5 Stereoselective Synthesis of S-Glycosides

6 Conclusion

A new heterogeneous polymeric disulfonimide was very easily synthesized from simple commercially available reagents. The new cost-effective catalytic material exhibited a tremendously enhanced reactivity in a benchmark Mukaiyama aldol reaction via silicon Lewis acid activation when compared with common acidic resins. Moreover, the reported polymeric disulfonimide exhibits outstanding robustness, as confirmed by its good thermal stability and excellent recyclability.

Studies on the transformations of some functionalized cycloalkene derivatives through their ring olefin-bond aziridination/aziridine opening with fluoride are presented. The selected model compounds submitted to fluorinative functionalization were an amino ester and diesters with a cyclohexene skeleton as well as a cyclopentene-fused β-lactam. Functionalization proceeded across a substrate-directed diastereoselective olefin-bond aziridination, followed by fluoride-mediated aziridine opening or intramolecular lactonization giving some fluorinated amino ester or amino lactone derivatives.

This account summarises our recent efforts (2020 to mid-2024) in designing and developing a handful of promising organic transformations for accessing several diversely functionalized biologically relevant organic scaffolds by following the green-chemistry principles with a particular focus on the application of low-energy visible light and electrochemistry. Mechanistic studies of each of these reactions established the involvement of a radical pathway.

1 Introduction

2 Green-Inspired Organic Transformations

2.1 Visible-Light-Driven Organic Synthesis

2.1.1 Synthesis of Functionalized Dihydrofuro[3,2-c]chromenones

2.1.2 Synthesis of Functionalized 2-(Aryl/alkylamino)-3-(aryl/alkylselanyl)naphthalene-1,4-diones and 2-(Arylamino)-3-(arylthio)naphthalene-1,4-diones

2.1.3 Synthesis of Functionalized 6-(Arylthio/arylseleno)benzo[a]phenazin-5-ols

2.1.4 Synthesis of Functionalized 3-(Alkyl/benzylthio)-4-hydroxy-2H-chromen-2-ones

2.1.5 Synthesis of Functionalized 2-Hydroxy-3-oxo-2,3-dihydrobenzofuran-2-carboxamides and 2-Hydroxy-3-oxo-2,3-dihydrobenzofuran-2-carboxylates

2.1.6 Synthesis of Functionalized 2-Hydroxyphenylated α-Ketoamides

2.2 Electrochemical Organic Synthesis

2.2.1 Synthesis of 3-Selenylated/Sulfenylated Derivatives of 2-Amino-1,4-naphthoquinones

2.2.2 Synthesis of Functionalized 6-(Arylthio/Arylseleno)benzo[a]phenazin-5-ols

2.2.3 Synthesis of Functionalized Alkyl 2-Hydroxy-3-oxo-2,3-dihydrobenzofuran-2-carboxylates

3 Conclusions

Cross-coupling reactions have been developed between C2-substituted 1-bromocyclobut-1-enes and Grignard reagents using two effective catalysts, e.g., Fe(acac)₃ and Ni(acac)₂. The iron catalyst works in THF but requires NMP as the co-solvent, with the advantage of achieving cross-coupling reactions with alkyl Grignard reagents. The nickel catalyst was able to promote the reactions in THF without any additive and showed high reactivity with electron-rich aryl Grignard reagents. These catalysts gave various types of substituted cyclobutenes in good yields.

Methyl 2-[bis(benzylthio)phosphoryl]acetate has proven to be an efficient Horner–Wadsworth–Emmons (HWE)-type reagent for the diastereodivergent synthesis of (E)- and (Z)-α,β-unsaturated esters. Under the conditions of excess NaHMDS relative to the HWE-type reagent, the HWE-type reactions of methyl 2-[bis(benzylthio)phosphoryl]acetate with various aldehydes afforded the corresponding α,β-unsaturated esters in an E-selective manner in up to 100:0 E/Z ratio. However, when an excess of the HWE-type reagent was used relative to NaHMDS, the stereoselectivity of the HWE-type reactions was dramatically changed from E to Z, yielding an E/Z ratio of up to 2:98.

In this research, we synthesized a novel mitochondrial-targeted antitumor lead compound named phenolthiazide-4C-Pvi (PCP) by modifying a phenothiazine with 3-(2-pyridin-4-ylvinyl)-1H-indole (Pvi) as a mitochondrial-targeted fluorescent cargo. Our preliminary findings indicated that PCP exhibits remarkable cell imaging and mitochondrial localization ability, and can induce apoptosis by influencing the membrane potential and reactive oxygen species levels in mitochondria. Compared with phenothiazines, PCP has an excellent ability to target the mitochondria of cancer cells, and its selectivity and toxicity to tumor cells are stronger than those toward normal cells. These results demonstrated that PCP possesses strong antitumor effects with excellent selectivity, making it a promising candidate as a mitochondrial-targeted antitumor drug.