Pyrazole based palladacycles for the synthesis of β-aminoketones by redox coupling of allyl alcohols and anilines

Herein, we report the synthesis of β-aminoketones by oxidative coupling of allyl alcohols at room temperature using a pyrazole based palladacycle and BINOL-phosphoric acid system. This method avoids the use of any base, external oxidant, and additive. The reaction of p-anisidine and 1-penten-3-ol under the optimized conditions using isolated palladacycle-BINOL-phosphoric acid produced the desired product in 24 h, which suggests that the active species involved in this reaction is the palladacycle-BINOL-phosphoric acid.

Palladium-Catalyzed Oxidation Reactions of Alkenes with Green Oxidants

Transition-metal-catalyzed oxidative functionalization of alkenes has emerged as a powerful and valuable tool in modern organic synthesis. Recently, many methods have been established for the assembly of C-C and C-heteroatom bonds, which provides tremendous possibility for application in biology, medicine, and materials science. However, the use of stoichiometric amounts of strong oxidants leads to poor selectivity, low atom economy, and a series of undesired waste products. By contrast, green oxidants, such as O₂ , H₂ O₂ , or tert-butyl hydroperoxide (TBHP), have bright prospects due to their attributes of mild, low cost, and great sustainability in transition-metal-catalyzed oxidation reactions. Based on the great and unique potential for the development of aerobic reactions, this review mainly highlights homogenous palladium-catalyzed green oxidations of alkenes that have been reported in recent years. These methods provide new strategies for the transformation and functionalization of alkenes; some of them have also been successfully applied to the synthesis of the core structures of drugs and natural products. Additionally, through in-depth studies of the reaction mechanisms in this field, it is believed that palladium-catalyzed green oxidation reactions of alkenes with O₂ , H₂ O₂ , or TBHP will create added value for organic synthetic chemistry.

Synthesis of amino acid derivatives of 5-alkoxy-3,4-dihalo-2(5H)-furanones and their preliminary bioactivity investigation as linkers

A series of amino acid derivatives are successfully synthesized via a metal-free C-N coupling reaction of 5-alkoxy-3,4-dihalo-2(5H)-furanones and amino acids. Their structures are well characterized with ¹H NMR, ¹³C NMR, ESI-MS and elemental analysis. As potential linkers of the 2(5H)-furanone unit with other drug moieties containing a hydroxyl or amino group, the effect of amino acids is investigated by comparison with other 2(5H)-furanone compounds by constructing C-O/C-S bonds. The preliminary results of the biological activity assay by the MTT method on a series of cancer cell lines in vitro reveal that the introduction of amino acids basically has no toxic effect. This can lead to these 2(5H)-furanone derivatives being further well-linked with other bioactive moieties with amino or hydroxy groups as expected. Thus, the biological activity assay gives a direction for the design of bioactive 2(5H)-furanones based on these amino acid linkers.