- A chemoselective route to β-enamino esters and thioesters
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Conditions were developed for syntheses of β-enamino esters, thioesters, and amides. These reactions involve hydroxybenzotriazole derivatives in buffered media. Illustrative syntheses of some heterocyclic systems are given, including some related to protein-protein interface mimics.
- Xin, Dongyue,Burgess, Kevin
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supporting information
p. 2108 - 2110
(2014/05/06)
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- 3-Nitrobenzeneboronic acid as an efficient and environmentally benign catalyst for the selective transesterification of β-keto esters
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An efficient and high-yielding procedure for the selective transesterification of various β-keto esters using 3-nitrobenzeneboronic acid as a catalyst in an environmentally acceptable process is described. Georg Thieme Verlag Stuttgart.
- Tale,Sagar,Santan,Adude
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p. 415 - 418
(2007/10/03)
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- Mg2+-imidazole-catalyzed self-condensation of malonyl thioesters: Getting tuned for biomimetic polyketide synthesis?
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We report that a subtle balance of carbanion reactivity, leaving group activation, and pKa of the catalyst is required for efficient self-condensation of thiomalonates to thioacetoacetates in up to 71% yield under "biomimetic" conditions originally proposed by Kobuke and Yoshida (Tetrahedron Lett. 1978, 19, 367).
- Sakai, Naomi,Sorde, Nathalie,Matile, Stefan
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p. 845 - 851
(2007/10/03)
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- A facile and selective procedure for transesterification of β-keto esters promoted by yttria-zirconia based lewis acid catalyst
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An yttria-zirconia based strong Lewis acid efficiently catalyses the transesterification of β-keto esters under environmentally safe, heterogeneous reaction conditions with high selectivity and in good to excellent yields.
- Kumar, Pradeep,Kumar Pandey, Rajesh
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p. 251 - 253
(2007/10/03)
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- Selective Catalytic Transesterification, Transthiolesterification, and Protection of Carbonyl Compounds over Natural Kaolinitic Clay
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Transesterification and transthiolesterification of β-keto esters with variety of alcohols and thiols and selective protection of carbonyl functions with various protecting groups catalyzed by natural kaolinitic clay are described. The clay has been found to be an efficient catalyst in transesterifying long chain alcohols, unsaturated alcohols, and phenols to give their corresponding β-keto esters in high yields. For the first time, transthiolesterification of β-keto esters with a variety of thiols has been achieved under catalytic conditions. Clay also catalyzes selective transesterification of β-keto esters by primary alcohols in the presence of secondary and tertiary alcohols giving corresponding β-keto esters. A systematic study involving the reactivity of different nucleophiles (alcohols, amines, and thiols) toward β-keto esters is also described. Sterically hindered carbonyl groups as well as α,β-unsaturated carbonyl groups underwent protection without the deconjugation of the double bond. Chemoselective protection of aldehydes in the presence of ketones has also been achieved over natural kaolinitic clay.
- Ponde, Datta E.,Deshpande, Vishnu H.,Bulbule, Vivek J.,Sudalai, Ammugam,Gajare, Anil S.
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p. 1058 - 1063
(2007/10/03)
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- Acetoacetylation with 2,2,6-Trimethyl-4H-1,3-dioxin-4-one: A Convenient Alternative to Diketene.
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The diketene/acetone adduct, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, efficiently acetoacetylates aliphatic and aromatic alcohols, amines, and thiols.These acetoacetylation reactions are fast and stoichiometric, require no catalysis, and give only volatile byproducts.
- Clemens, Robert J.,Hyatt, John A.
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p. 2431 - 2435
(2007/10/02)
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