for palladium-catalyzed oxidative deacetonative coupling of 4-aryl-2-methyl-3-butyn-2-ols with dialkylH-phosphonates has been developed. This methodology provides a new and practical route to alkynylphosphonates using the inexpensive 4-aryl-2-methyl-3-butyn-2-ols as the alkyne sources. This reaction could also be performed with aryl bromides, 2-methyl-3-butyne-2-ol and dialkylH-phosphonates using
different palladium complexes of sydnones and sydnone imines and a co-catalyst system consisting of lithium sydnone-4-carboxylate and Pd(PPh3)4 catalyzed Sonogashira-Hagihara reactions between (hetero)aromatic bromides and 2-methylbut-3-yn-2-ol (52 examples, up to 100% yield). The co-catalyst system and a sydnone Pd complex were also tested in Buchwald-Hartwig reactions (9 examples, up to 100% yield)
Iridium-Catalyzed Cyclative Indenylation and Dienylation through Sequential B(4)–C Bond Formation, Cyclization, and Elimination from <i>o</i>-Carboranes and Propargyl Alcohols
作者:Yonghyeon Baek、Kiun Cheong、Gi Hoon Ko、Gi Uk Han、Sang Hoon Han、Dongwook Kim、Kooyeon Lee、Phil Ho Lee
DOI:10.1021/jacs.0c02121
日期:2020.6.3
indenylation through sequential B(4)-C and intramolecular C-C bond formation from o-carboranes and propargyl alcohols, leading to the formation of B(4)-indenylated-o-carboranes with excellent regioselectivity via direct B-H activation. Moreover, the iridium-catalyzed regioselective 1,3-dienylation has been accessed through sequential B-H activation, dehydration, and decarboxylation, producing B(4)-dienylated-o-carboranes
Synthesis of 2-Arylindoles by Rhodium-Catalyzed/Copper-Mediated Annulative Coupling of<i>N</i>-Aryl-2-aminopyridines and Propargyl Alcohols via Selective C–H/C–C Activation
A versatile rhodium-catalyzed/copper-mediated C-H/C-C activation and cascade annulationreaction was described to form 2-arylindole derivatives. Highly selective C-C bond cleavage of γ-substituted tert-propargyl alcohols occurred, together with pyridine-directed ortho C(sp2)-H bond activation, affording a series of 2-arylindoles with yields up to 90%. Subsequent derivations were smoothly conducted
A general and efficient synthesis of trifluoromethyl substituted 5-alkylidene-1,3-dioxolane using a silver salt and DBU cooperatively catalyzed nucleophilic addition/cyclization of propargylic alcohols and trifluoromethyl ketones is described. The procedure produced 5-alkylidene-1,3-dioxolane derivatives with good to excellent yields and can be used with a broad range of substrates.