- Copper Bis(oxazoline)-Catalyzed Enantioselective Alkynylation of Benzopyrylium Ions
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The stereocontrolled construction of biologically relevant chromanones and tetrahydroxanthones has been achieved through the addition of alkynes to benzopyrylium trilfates under the influence of copper bis(oxazoline) catalysis. Excellent levels of enantiocontrol (63–98 % ee) are achieved in the addition of a variety of alkynes to an array of chromenones with a hydrogen in the 2-position. Promising levels of enantiocontrol (54–67 % ee) are achieved in the alkynylation of chromenones with esters in the 2-position, generating tertiary ether stereocenters resembling those frequently found in naturally occurring metabolites.
- Guan, Yong,Attard, Jonathan W.,Mattson, Anita E.
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- Synthesis of Allylboranes via Cu(I)-Catalyzed B-H Insertion of Vinyldiazoacetates into Phosphine-Borane Adducts
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Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with high diastereoselectivity and yields 5,6-disubstituted dihydropyranones after treatment with an appropriate acid.
- Drikermann, Denis,M??el, Robert S.,Al-Jammal, Walid K.,Vilotijevic, Ivan
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supporting information
p. 1091 - 1095
(2020/02/15)
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- Lewis Acid-Catalyzed [3+2] Cycloaddition of Donor-Acceptor Cyclopropanes and Enamines: Enantioselective Synthesis of Nitrogen-Functionalized Cyclopentane Derivatives
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A straightforward and efficient method for the synthesis of nitrogen-functionalized cyclopentane derivatives via [3+2] cycloaddition of enamines with donor-acceptor cyclopropanes in the presence of catalytic amounts of various Lewis acids at room temperat
- Verma, Kamal,Banerjee, Prabal
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p. 2053 - 2058
(2016/07/16)
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- Homogeneous asymmetric hydrogenation catalyst
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Provide that a useful catalyst for homogeneous hydrogenation, particularly a catalyst for homogeneous asymmetric hydrogenation for hydrogenation, particularly asymmetric hydrogenation, which is obtainable with comparative ease and is excellent in economically and workability, and a process for producing a hydrogenated compound of an unsaturated compound, particularly an optically active compound using said catalyst with a high yield and optical purity.
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- Dehydrative cyclization of serine, threonine, and cysteine residues catalyzed by molybdenum(VI) oxo compounds
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Commercially available molybdenum(VI) oxides such as (NH4)2MoO4, (NH4)6Mo7O24·4H2O, MoO2(acac)2, and MoO2(TMHD)2 are highly
- Sakakura, Akira,Kondo, Rei,Umemura, Shuhei,Ishihara, Kazuaki
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body text
p. 2102 - 2109
(2009/07/11)
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- Synthesis of non-symmetric bisoxazoline compounds. An easy way to reach tailored chiral ligands
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Bisoxazoline compounds have been used as chiral catalyst ligands in a wide variety of reactions. A great deal of effort has been aimed at the synthesis of C2-symmetric bisoxazolines but very few references exist for non-symmetric ones. As part of our studies into the possible usefulness of non-symmetric bisoxazolines, we report an easy method for the synthesis of bisoxazoline compounds bearing different substituents in each oxazoline ring.
- Garcia, Jose I.,Mayoral, Jose A.,Pires, Elisabet,Villalba, Isabel
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p. 2270 - 2275
(2007/10/03)
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- An efficient and general one-pot method for the synthesis of chiral bis(oxazoline) and pyridine bis(oxazoline) ligands
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An expeditious method for the synthesis of chiral box and pybox ligands is reported. The approach is based on a one-pot condensation reaction of chiral β-amino alcohols with a dinitrile using stoichiometric or catalytic amounts of zinc triflate. Yields gr
- Cornejo,Fraile,García,Gil,Martínez-Merino,Mayoral,Pires,Villalba
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p. 2321 - 2324
(2007/10/03)
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- Molybdenum oxides as highly effective dehydrative cyclization catalysts for the synthesis of oxazolines and thiazolines
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(Chemical Equation Presented) In the presence of molybdenum oxide the dehydrative cyclization of N-acylserines, N-acylthreonines, and N-acylcysteines can be carried out under Dean-Stark conditions in toluene to give oxazolines and thiazolines. The ammoniu
- Sakakura, Akira,Kondo, Rei,Ishihara, Kazuaki
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p. 1971 - 1974
(2007/10/03)
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