- Simple and efficient heterogeneous copper catalysts for enantioselective C-H carbene insertion
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Immobilized box-Cu complexes are able to efficiently catalyze the insertion of a carbene, from methyl phenyldiazoacetate, into C-H bonds of THF, with high enantioselectivity (up to 88% ee). The immobilization not only allows recovery and reuse of the enan
- Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.,Roldan, Marta
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- An efficient synthesis of indane-derived bis(oxazoline) and its application to hetero Diels-Alder reactions on polymer support
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Indane-derived bis(oxazolines) were synthesized in two steps and 93% overall yield starting from commercially available substrates. This ligand is as effective as tert-butyl bis(oxazoline) in hetero Diels-Alder reaction both in solution and on polymer sup
- Kurosu, Michio,Porter, James R.,Foley, Michael A.
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- SYNTHESIS OF SMALL MOLECULES INSPIRED BY PHOMOXANTHONE A
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Methods, compositions, and kits are provided for synthesizing bioactive chromane, the method including: constructing a tertiary ether stereocenter enantioselectively by catalyzed alkynylation of a substituted chromenone to obtain a chromanone; reducing alkyne and ketone in the chromanone to obtain a chroman; and converting ester to methyl group thereby obtaining chromane.
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- 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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p. 1742 - 1747
(2020/02/05)
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- Ethynylbenziodazolones (EBZ) as Electrophilic Alkynylation Reagents for the Highly Enantioselective Copper-Catalyzed Oxyalkynylation of Diazo Compounds
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Ethynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents are now established reagents for the alkynylation of radicals and nucleophiles, yet they present limited possibilities for further structure and reactivity modification. Herein, the first synthesis is reported for the corresponding ethynylbenziodazolone (EBZ) reagents, in which the oxygen atom in the iodoheterocycle is replaced by a nitrogen atom. The substituent on the nitrogen enables further fine-tuning of the reagent structure and reactivity. EBZ reagents are obtained easily from the corresponding benzamides by using a one-step procedure, and display reactivity comparable to that of EBX reagents. In particular, they are applied in an asymmetric copper-catalyzed oxyalkynylation of diazo compounds, which proceeds in high yield and enantioselectivity for a broad range of substituents on the diazo compounds and the alkyne.
- Hari, Durga Prasad,Schouwey, Lionel,Barber, Verity,Scopelliti, Rosario,Fadaei-Tirani, Farzaneh,Waser, Jerome
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supporting information
(2019/05/28)
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- Enantioselective Copper-Catalyzed Oxy-Alkynylation of Diazo Compounds
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Enantioselective catalytic methods allowing the addition of both a nucleophile and an electrophile onto diazo compounds give a fast access into important building blocks. Herein, we report the highly enantioselective oxyalkynylation of diazo compounds usi
- Hari, Durga Prasad,Waser, Jerome
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supporting information
p. 8420 - 8423
(2017/07/06)
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- Copper(II)-catalyzed enantioselective intramolecular cyclization of N-alkenylureas
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The first Cu(II)-catalyzed highly enantioselective intramolecular cyclization of N-alkenylureas was developed for the concise assembly of chiral vicinal diamino bicyclic heterocycles. Facile removal of carbonyl group of the carbamido moiety allowed for ready access to enantioenriched cyclic vicinal diamines.
- Fu, Shaomin,Yang, Honghao,Deng, Yuanfu,Jiang, Huanfeng,Zeng, Wei,Li, Guoqiang
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supporting information
p. 1018 - 1021
(2015/03/30)
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- Exploring structural diversity in ligand design: The aminoindanol case
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A series of enantiopure ligands based on the aminoindanol scaffold, but differing in regio-and stereochemistry has been synthesized. These ligands have been conveniently derivatized and their catalytic efficiency in different enantioselective reactions has been screened to determine privileged candidates with respect to regio- and stereochemistry for each considered process. The nature of the amino substituent has been optimized for specific applications and this has led to the development of an efficient method for the preparation of bulky bicyclic amines by reductive amination.
- Rodriguez-Escrich, Sergi,Sola, Lluis,Jimeno, Ciril,Rodriguez-Escrich, Carles,Pericas, Miquel A.
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supporting information; experimental part
p. 2250 - 2260
(2009/10/06)
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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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- A new method for recycling asymmetric catalysts via formation of charge transfer complexes
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A new concept for recycling asymmetric bis(oxazoline)-type catalysts is reported. The formation of charge-transfer complexes between the chiral ligand and trinitrofluorenone and their subsequent precipitation and reuse by addition of new substrate solutions is described. The efficiency of this procedure is demonstrated in a Diels-Alder reaction to reach the expected endo product as major isomer (up to 97% de and 94% ee): the catalyst was used up to 12 times without loss of either activity or selectivity.
- Chollet, Guillaume,Rodriguez, Fernand,Schulz, Emmanuelle
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p. 539 - 542
(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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- Allylic amination of unfunctionalyzed olefins by nitroarenes and CO, catalyzed by Ru3(CO)12/Ph-BIAN (Ph-BIAN=bis(phenylimino) acenaphthenequinone): Extension to the synthesis of allylic amines with strongly electron-withdrawing or el
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The allylic amination of unfunctionalyzed olefins by nitroarenes under CO pressure, catalyzed by Ru3(CO)12/Ph-BIAN (Ph-BIAN=bis(phenylimino)acenaphthenequinone) has been extended to some substrates with strongly electron-withdrawing
- Ragaini, Fabio,Cenini, Sergio,Turra, Fabrizio,Caselli, Alessandro
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p. 4989 - 4994
(2007/10/03)
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- Application of a Ritter-type reaction to the synthesis of chiral indane-derived C2-symmetric bis(oxazolines)
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Bis(oxazolines) 4, 6, 8, 9, 10, and 11 are prepared in a highly regio- and diastereo-selective manner from dinitriles and indanediol 3 in a Ritter-type reaction initiated by trifluoromethanesulfonic acid.
- Davies, Ian W.,Senanayake, Chris H.,Larsen, Robert D.,Verhoeven, Thomas R.,Reider, Paul J.
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p. 813 - 814
(2007/10/03)
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