Synthesis of Enaminone‐Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki‐Miyaura Cross Coupling Reaction

Abstract

Summary of main observation and conclusion A series of Pd(II)‐enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)‐reagents has proved that the Pd(eao)2‐1 possesses excellent catalytic activity for the Suzuki‐ Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)‐reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2‐2 has been found as a practical catalyst for the homo‐coupling reactions of aryl boronic acids.

Recent Advances in Reactions Using Enaminone in Water or Aqueous Medium

“…[2] Interestingly, due to the similarity in structure, enaminones have been regarded and utilized mainly as the aza-equivalent of enols for rather long period, which has actually hampered the advances of enaminone chemistry. Therefore, the discovery of distinctive transformation modes, such as the functionalization of the internally activated vinyl CÀ H bond, [3] the amine-elimination promoted aryl ring construction, [4] the cleavage of the C=C double bond by different pathways, [5] the coupling functionalization of the alkenyl CÀ N bond, [6] the application in catalytic cross coupling processes by chelating transition metal catalyst, [7] as well as miscellaneous other novel reactions [8] in enaminones have opened new frontiers for enaminone-based synthetic chemistry.…”

Preparation of Thioaminals in Water

“…Recently, there has been an increased concern about the development of sustainable methodologies [ 24 , 25 , 26 , 27 ], including procedures in water [ 28 , 29 , 30 , 31 , 32 ]. With this in mind, our group (i) focused on the valorization of raw renewable materials such as furfural and hydroxymethylfurfural (HMF) [ 33 , 34 , 35 ] and (ii) reported on the use of water as a green reaction media for the production of cyclopentenones [ 36 ] and, more recently, aminals from the condensation of aryl aldehydes with amines [ 37 ].…”

Rhodium-Catalyzed Decarbonylative Suzuki-Miyaura Cross-Coupling via in-Situ Generation of Acyl Fluorides from Carboxylic Acids

“…[13] Suzuki-Miyaura coupling, a renowned and robust method to connect carbon-carbon bond for assembling complicated molecules, has recently became hot-topic issue that fascinated numerous chemists. [14] To the best of our knowledge, there is no document describing the rhodium catalyzed decarbonylative Suzuki-Miyaura crosscoupling via in-situ generation of acyl fluorides from carboxylic acids, which stimulated us to actualize this envision.…”