We present an advancement in synthesizing organophosphorus compounds via chemoselective phosphorylation achieved by a palladium and SelectPhos ligand system (Pd/). This catalysis system exhibits remarkable chemoselectivity, even in poly(pseudo)halide substrates and overcoming toxicity and substrate scope limitations. The catalytic system is robust, which is demonstrated across diverse substrates such as chloroaryl and bromoaryl triflates.
View Article and Find Full Text PDFIn this study, a novel and efficient Pd-catalyzed chemoselective deuterodehalogenation reaction of halogenated aryl triflates was developed using isopropanol- as the deuterium source. This chemoselective reaction afforded an unconventional chemoselectivity order of C-Br > C-Cl > C-OTf. This catalytic system was successfully applied to chemoselective hydrodehalogenation of chloroaryl triflates, providing excellent C-Cl chemoselectivity over C-OTf.
View Article and Find Full Text PDFThis study described palladium-catalyzed chemoselective direct α-arylation of carbonyl compounds with chloroaryl triflates in the Ar-Cl bond. The Pd/SelectPhos system showed excellent chemoselectivity toward the Ar-Cl bond in the presence of the Ar-OTf bond with a broad substrate scope and excellent product yields. The electronic and steric hindrance offered by the -PR group of the ligand with the C2-alkyl group was found to be the key factor affecting the reactivity and chemoselectivity of the α-arylation reaction.
View Article and Find Full Text PDFA novel family of indole-amide-based phosphine ligands was designed and synthesized. The Pd/InAm-phos (L1) catalytic system exhibited excellent efficiency in the Suzuki-Miyaura cross-coupling of sterically hindered (hetero)aryl chlorides to synthesize tri--substituted biaryls. Excellent product yields were obtained in a short reaction time (, 10 min), and a Pd catalyst loading down to 50 ppm was also achieved.
View Article and Find Full Text PDFWith a tandem DMAP-catalyzed reaction between -AQM, in which it is generated in situ from propargylic amine, and acyl carbene surrogate (from pyridinium ylide), a variety of polyarylated chromenes are assembled in good yields. This process does not require transition-metal catalyst and exhibits easy manipulation of the arene group and good functional group compatibility, particularly the -Br group which can be further transformed to other functionalities by cross-coupling reactions. The modular feature of -AQM substrates and the simple operation procedures add further advantages to this synthetic method.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2020
This study describes the first palladium-catalyzed, site-selective α- and γ-arylation of α,β-unsaturated ketones with (hetero)aryl halides. A wide range of hetero(aryl)halides coupled with α,β-unsaturated ketones, and transformation into the arylated products proceeded with excellent to good yields. The site selectivity of the reaction is switchable by simply changing the phosphine ligand to access either α-arylated or γ-arylated products in good to excellent yields by using a low catalyst loading, and the method demonstrates good functional-group compatibility.
View Article and Find Full Text PDFA DMAP-catalyzed cascade approach allowing facile assembly of alkynyl coumarins is reported. By virtue of reactive -AQM (in situ generated from modular propargylamine) and a new synthetic equivalent of acyl carbene (from pyridinium ylide), the reaction proceeds smoothly to afford a variety of alkynyl coumarins in good-to-excellent yields. This transition-metal-free and oxidant-free process features moderate functional group tolerance, particularly the -Br group; thus, this protocol circumvents the inherent shortcomings of the existing Sonogashira coupling of coumarin triflates.
View Article and Find Full Text PDFFacile access to π-extended heterobiaryl compounds via a non-cross-coupling strategy has been achieved. In the presence of an inexpensive ZnI2 catalyst and versatile propargylamine and β-naphthol (or β-naphthylamine and β-naphthyl mercaptan) starting materials, a variety of sterically hindered heterobiaryl frameworks can be easily obtained. The present catalytic system offers excellent selectivity, good-to-excellent product yields, and good functional group tolerance including, for instance, -CN, -COOH, -C(O)R, -Br and -Cl groups.
View Article and Find Full Text PDFThe first general examples of direct C-H arylation of electron-deficient polyfluoroarenes with challenging di- ortho-substituted aryl(heteroaryl) chlorides for tetra- ortho-substituted biaryl synthesis are reported. Key to success is the use of Buchwald-type biaryl phosphine ligand, notably with inexpensive -PPh moiety (instead of -PCy group). Pd(OAc) associated with ligand L9 exhibits even higher efficiency than the corresponding SPhos toward this reaction.
View Article and Find Full Text PDFThe first general palladium catalyst for the catalytic mono-α-arylation of aryl- and heteroarylketones with aryl mesylates and tosylates is described. The newly developed indolyl-derived phosphine ligand L7 has been identified to promote this reaction efficiently. The key to success is attributed to the enhanced steric congestion of the catalyst and effective oxidative addition of the C(Ar)-OMs bond.
View Article and Find Full Text PDFA general palladium-catalyzed Hiyama cross-coupling reaction of aryl and heteroaryl chlorides with aryl and heteroaryl trialkoxysilanes by a Pd(OAc)2 /L2 catalytic system is presented. A newly developed water addition protocol can dramatically improve the product yields. The conjugation of the Pd/L2 system and the water addition protocol can efficiently catalyze a broad range of electron-rich, -neutral, -deficient, and sterically hindered aryl chlorides and heteroaryl chlorides with excellent yields within three hours and the catalyst loading can be down to 0.
View Article and Find Full Text PDFThe rational design of a phosphine ligand for the reductive elimination-demanding Pd-catalyzed mono-α-arylation of acetone is demonstrated and reported. The catalyst is tolerant of previously proven challenging electron-deficient aryl chlorides and provides excellent product yields with down to 0.1 mol % Pd.
View Article and Find Full Text PDFThe first general examples of direct coupling of heteroaryl chlorides, especially substituted 2-pyridyl chlorides which were previously found to be problematic, with electron-deficient polyfluoroarenes are reported. Pd(OAc)2 associated with 3-(dicyclohexylphosphino)-2-phenylindole L1 serves as the effective catalyst which allows the challenging direct coupling of heteroaryl chlorides and polyfluoroarenes. In addition to heterocycles, a wide range of non-activated and activated aryl chlorides and alkenyl chlorides were also applicable under this catalyst system.
View Article and Find Full Text PDFObjective: To review the performance of non-invasive prenatal testing (NIPT) by low-coverage whole-genome sequencing of maternal plasma DNA at a single center.
Methods: The NIPT result and pregnancy outcome of 1982 consecutive cases were reviewed. NIPT was based on low coverage (0.
Copper-mediated direct and regioselective C3-cyanation of indoles using benzyl cyanide as the cyanide anion source is presented. A wide range of indoles undergo cyanation smoothly by employing a reaction system of copper(I) iodide under open-to-air vessels.
View Article and Find Full Text PDFThis study describes the application of indolylphosphine ligands with a diphenylphosphino moiety to the palladium-catalyzed borylation of aryl chlorides. The combination of palladium metal precursor with PPh(2)-Andole-phos, which comprises an inexpensive -PPh(2) group, provides highly effective catalysts for the borylation of aryl chlorides. A range of functional groups such as -CN, -NO(2), -CHO, -COMe, -COOMe, and -CF(3) was compatible, and the catalyst loading down to 0.
View Article and Find Full Text PDFBackground: Controversy surrounds the relationship between tardive dyskinesia (TD) and symptoms of schizophrenia. While some studies reported that negative symptoms of schizophrenia may be a risk factor for TD, others reported a relationship between TD and positive symptoms.
Method: Eighty-four patients were studied, of whom 47 met criteria for TD.
J Psychiatry Neurosci
November 1994