在金属三氟甲磺酸酯催化的炔烃加氢芳基化中,采用离子液体显着增强了催化活性,从而扩大了底物(芳烃和炔烃)的范围。在某些情况下,甚至在常规有机溶剂中不可能发生的反应在离子液体中也能顺利进行。而且,通过在反应后简单地倾析有机层,可以容易地回收含离子液体的催化剂,并且可以将其重新用于随后的运行中而没有任何明显的活性损失。包括反应中间体的13 C NMR分析和同位素实验在内的机理研究首次证实,这种类型的反应是通过乙烯基阳离子中间体进行的。
Silver-catalyzed carbon–phosphorus functionalization of N-(p-methoxyaryl)propiolamides coupled with dearomatization: access to phosphorylated aza-decenones
We developed a green method for the synthesis of spiro[4.5]trienones through an electrochemical oxidative halocyclization with N-aryl alkynamides. This reaction was conducted under metal-catalyst- and exogenous-oxidant-free conditions at room temperature. Using readily available LiCl, LiBr, and LiI as the halogen source, a variety of dearomative halo-spirocyclization products were obtained in good
We describe herein a general approach to napthyridinones via the Pd-catalyzed annulation of 1,6-enynes with 2-iodoanilines. This protocol represents a rare carbo-aminative annulative cyclization via the 6-endo-trig mode, subduing the well-documented exo-trig/dig cyclizations. The regioselective aryl palladation of alkyne followed by Heck-type intramolecular coupling before isomerization were key in
Pd‐Catalyzed Vicinal Intermolecular Annulations of Iodoarenes, Indoles, and Carbazoles with Enynes
作者:Undamatla Suri Babu、Ramesh Kotipalli、Jagadeesh Babu Nanubolu、Maddi Sridhar Reddy
DOI:10.1002/chem.202302788
日期:2024.2
A vicinal annulation of 2-iodobenzoates, indoles, and carbazoles with 1,6-enynes is described. The relay involved 7-/8-membered palladacycles, leading to multicyclic scaffolds, which were readily diversified to an array of adducts (with new functional tethers and/or three contiguous stereocenters), in which a challenging benzylic monooxygenation was showcased.
A new and general method has been developed for preparation of coumarins and quinolinones by intramolecular hydroarylation of alkynes. Various aryl alkynoates and alkynanilides undergo fast intramolecular reaction at room temperature in the presence of a catalytic amount of Pd(OAc)(2) in a mixed solvent containing trifluoroacetic acid (TFA), affording coumarins and quinolinones in moderate to excellent yields with more than 1000 turnover numbers (TON) to Pd. The methodology proved to tolerate a number of functional groups such as Br and CHO. On the basis of isotope experiments, a possible mechanism involving ethynyl chelation-assisted electrophilic metalation of aromatic C-H bonds by in-situ generated cationic Pd(II) species has been discussed. Also the involvement of vinylcationic species has been suggested.
Dramatic Enhancement of Catalytic Activity in an Ionic Liquid: Highly Practical Friedel-Crafts Alkenylation of Arenes with Alkynes Catalyzed by Metal Triflates
作者:Choong Eui Song、Da-un Jung、Su Yhen Choung、Eun Joo Roh、Sang-gi Lee