Publications by authors named "Ying-Kit Chung"

6 Publications

  • Page 1 of 1

Catalytic asymmetric C-N bond formation: phosphine-catalyzed intra- and intermolecular γ-addition of nitrogen nucleophiles to allenoates and alkynoates.

Angew Chem Int Ed Engl 2013 Feb 21;52(9):2525-8. Epub 2013 Jan 21.

Division of Chemistry and Chemical Engineering, California, Institute of Technology, Pasadena, CA 91125, USA.

Pin the amine on the gamma: A new method has been developed for the γ-addition of nitrogen nucleophiles to γ-substituted alkynoates or allenoates through intra- and intermolecular processes that are catalyzed by spirophosphine 1. An asymmetric version of this reaction affords enantioenriched pyrrolidines, indolines, and γ-amino-α,β-unsaturated carbonyl compounds.
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http://dx.doi.org/10.1002/anie.201208957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819219PMC
February 2013

Phosphine-catalyzed enantioselective synthesis of oxygen heterocycles.

Angew Chem Int Ed Engl 2009 ;48(12):2225-7

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Chiral phosphepine 1 catalyzes the transformation of an array of hydroxy-2-alkynoates into saturated oxygen heterocycles with good enantioselectivity. Phenols are also shown to participate in such phosphine-catalyzed cyclizations, including an asymmetric variant. This method provides a new approach to the enantioselective synthesis of tetrahydrofurans, tetrahydropyrans, and dihydrobenzopyrans.
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http://dx.doi.org/10.1002/anie.200805377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2747790PMC
May 2009

Intramolecular cyclopropanation of unsaturated terminal epoxides and chlorohydrins.

J Am Chem Soc 2007 Apr 21;129(14):4456-62. Epub 2007 Mar 21.

Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.

Lithium 2,2,6,6-tetramethylpiperidide (LTMP)-induced intramolecular cyclopropanation of unsaturated terminal epoxides provides an efficient and completely stereoselective entry to bicyclo[3.1.0]hexan-2-ols and bicyclo[4.1.0]heptan-2-ols. Further elaboration of C-5 and C-6 stannyl-substituted bicyclo[3.1.0]hexan-2-ols via Sn-Li exchange/electrophile trapping or Stille coupling generates a range of substituted bicyclic cyclopropanes. An alternative straightforward cyclopropanation protocol using a catalytic amount of 2,2,6,6-tetramethylpiperidine (TMP) allows for a convenient (1 g-7.5 kg) synthesis of bicyclo[3.1.0]hexan-2-ol and other bicyclic adducts. The synthetic utility of this chemistry has been demonstrated in a concise asymmetric synthesis of (+)-beta-cuparenone. The related unsaturated chlorohydrins also undergo intramolecular cyclopropanation via in situ epoxide formation.
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http://dx.doi.org/10.1021/ja0672932DOI Listing
April 2007

N-Tetrahydroquinolinyl, N-quinolinyl and N-isoquinolinyl biaryl carboxamides as antagonists of TRPV1.

Bioorg Med Chem Lett 2006 Sep 27;16(17):4533-6. Epub 2006 Jun 27.

Neurology and GI Center of Excellence for Drug Discovery, GlaxoSmithKline, New Frontiers Science Park, Harlow, Essex, UK.

Starting from the high throughput screening hit (3), novel N-tetrahydroquinolinyl, N-quinolinyl and N-isoquinolinyl carboxamides have been identified as potent antagonists of the ion channel TRPV1. The N-quinolinylnicotinamide (46) showed excellent potency at human, guinea pig and rat TRPV1, a favourable in vitro DMPK profile and activity in an in vivo model of inflammatory pain.
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http://dx.doi.org/10.1016/j.bmcl.2006.06.026DOI Listing
September 2006

Intramolecular cyclopropanation of unsaturated terminal epoxides.

J Am Chem Soc 2004 Jul;126(28):8664-5

Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.

Efficient lithium amide-induced intramolecular cyclopropanation of bishomoallylic and trishomoallylic epoxides is described. The methodology is used in an asymmetric synthesis of sabina ketone.
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http://dx.doi.org/10.1021/ja047346kDOI Listing
July 2004

An unsaturated peptidomimetic assembly derived from a carbohydrate.

J Pept Sci 2004 Jan;10(1):1-7

Dyson Perrins Laboratory, University of Oxford, OX1 3QY, UK.

A strategy has been established for the synthesis of peptidomimetics derived from unsaturated carbohydrates, and exemplified by the use of methyl 2,6-anhydro-7-azido-3,7-deoxy-4,5-O-isopropylidene-D-lyxo-hept-2-enonate 9 as a dipeptide 'monomer' which can be elaborated from either end. Selective reduction of 9 gives a protected pseudodipeptide ester suitable for use as an amino component, and saponification gives an azido acid suitable for use as a carboxyl component. The 'dimer' product of coupling these two components with TBTU can be similarly elaborated at either end to give a 'trimer' and a further cycle of selective reduction and coupling gave a 'tetramer', 17, a pseudo-octapeptide.
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http://dx.doi.org/10.1002/psc.488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7167831PMC
January 2004