II. Preparation of N1* and CsOPh • H2OThe yields have not been optimized. Preparation of N,N-dimethyl-1,2-bis(4-(trifluoromethyl)phenyl)ethane-1,2-diamine (N1*).In accordance with a literature procedure, 2 under a nitrogen atmosphere, a three neck round-bottom flask (500 mL) was charged with Zn dust (325 mesh; 19.6 g, 300 mmol) and anhydrous acetonitrile (75 mL). To activate the Zn, 1,2-dibromoethane (5.25 g, 28 mmol) was added, and the mixture was brought to reflux for 1 min, then allowed to cool to room temperature; next, a small amount of TMSCl (4.8 mL, 38 mmol) was added, whereupon the evolution of gas (ethylene) was observed. The mixture was stirred for 45 min, and then a solution of N-methyl-1-(4-(trifluoromethyl)phenyl)methanimine (56.2 g, 300 mmol) in acetonitrile (150 mL) was added in one portion. TMSCl (57 mL, 450 mmol) was added slowly at a rate to maintain the internal temperature below 35-40 °C. After completion of the addition, the mixture was stirred for 1 h, and then it was cooled to 0 °C and cautiously hydrolyzed with a mixture of aqueous NH4OH (90 mL) and a saturated aqueous solution of NH4Cl (200 mL). The excess Zn was removed by filtration, the organic phase was separated, and the aqueous phase extracted with CH2Cl2 (3x150 mL). The combined organic phase was dried over anhydrous Na2SO4, filtered, and concentrated on a rotary evaporator, resulting in a semi-solid residue. The diamine was dissolved in absolute EtOH (600 mL), and racemic tartaric acid (150 mmol, 22.2 g) was added. The heterogeneous mixture was brought to reflux for 30 min. After cooling to room temperature, the precipitate was collected by filtration and washed twice with EtOH (2x70 mL). To the obtained precipitate was then added EtOH (200 mL), and the heterogeneous mixture was brought to reflux again for 30 min. After cooling to room temperature, the precipitate was collected by filtration and washed twice with EtOH (2x30 mL). The precipitate was poured into a mixture of an aqueous solution of 35% NaOH (100 mL) and Et2O (200 mL). The resulting mixture was stirred for 30 min, and then the phases were separated. The aqueous phase was extracted with Et2O (3x150 mL), and the combined organic phase was dried over anhydrous Na2SO4, filtered, and concentrated to afford pure d,ldiamine ligand N1 (18.0 g, 32% yield).(L)-Tartaric acid (7.18 g, 47.9 mmol) was added to pure d,l-diamine ligand N1 (18.0 g, 47.9 mmol) in EtOH (200 mL), and the resulting mixture was refluxed for 30 min. After cooling to room temperature, the precipitate was collected by filtration and washed with EtOH (2x10 mL), while the mother liquor was set aside. EtOH (100 mL) was added to the precipitate, and the resulting mixture was refluxed again for 30 min. After cooling to room temperature, the precipitate was collected by filtration and washed with EtOH (2x10 mL). The precipitate was added to a mixture of an aqueous solution of 35% NaOH (60 mL) and Et2O (200 mL). The resulting mixture was stirred for 30 min, and the phases were separated. The aqueous phase was extrac...
Photoinduced, copper-catalyzed coupling reactions are emerging as a powerful method for generating Csp3–Y (Y = C or heteroatom) bonds from alkyl electrophiles and nucleophiles. Corresponding three-component couplings of alkyl electrophiles, olefins, and nucleophiles have the potential to generate an additional Csp3–Y bond and to efficiently add functional groups to both carbons of an olefin, which serves as a readily available linchpin. In this report, we establish that a variety of electrophiles and a trifluoromethylthiolate nucleophile can add across an array of olefins (including styrenes and electron-poor olefins) in the presence of CuI/binap and blue-LED irradiation, thereby generating trifluoromethyl thioethers in good yield. The process tolerates a wide range of functional groups, and an initial survey of other nucleophiles (i.e., bromide, cyanide, and azide) suggests that this three-component coupling strategy is versatile. Mechanistic studies are consistent with a photoexcited Cu(I)/binap/SCF3 complex serving as a reductant to generate an alkyl radical from the electrophile, which likely reacts in turn with the olefin and a Cu(II)/SCF3 complex to afford the coupling product.
Transition-metal-catalyzed alkoxycarbonylation reactions usually involve aryl halide ArX as the electrophile and CO/ ROH as the nucleophile (Scheme 1, Path 1). As an alternative avenue, the oxidative carbonylation between an aryl metal ArM and CO/ROH by employing stoichiometric amount of oxidants has recently attracted increasing attention (Scheme 1, Path 3). Apparently, if simple arenes ArH were directly employed as the nucleophile and air or O 2 as the terminal oxidant in oxidative carbonylation, this challenging transformation will present an attractive and sustainable approach towards the synthesis of carbonyl compounds (Scheme 1, Path 2).Carboxylic acids and derivatives (e.g., esters) are valuable commodity chemicals and useful synthetic building blocks for agrochemicals, active pharmaceutical ingredients and process chemicals. Since the pioneering work of Heck and co-workers in 1974, [1] transition-metal-catalyzed carbonylation reactions of aromatic halides ArX in the presence of CO and ROH affording ArCO 2 R have undergone rapid development and been widely applied in industry in the last several decades, [2] whereas ArX is usually prepared from the corresponding ArH and a stoichiometric amount of bases is required to facilitate the reaction.
A series of modular and rich electronic tridentate ferrocene aminophosphoxazoline ligands (f-amphox) have been successfully developed and used in iridium-catalytic asymmetric hydrogenation of simple ketones to afford corresponding enantiomerically enriched alcohols under mild conditions with superb activities and excellent enantioselectivities (up to 1 000 000 TON, almost all products up to >99% ee, full conversion). The resulting chiral alcohols and their derivatives are important intermediates in pharmaceuticals.
This review covers the recent studies featuring the development of catalysts for alkene hydroaminomethylation.
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