Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones
نویسندگان
چکیده
منابع مشابه
Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones.
A synthetic approach for the preparation of a new class of highly conjugated unnatural α-amino acids bearing a 5-arylpyrazole side-chain has been developed. Horner-Wadsworth-Emmons reaction of an aspartic acid derived β-keto phosphonate ester with a range of aromatic aldehydes gave β-aryl α,β-unsaturated ketones. Treatment of these with phenyl hydrazine followed by oxidation allowed the regiose...
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A general and simple procedure to access chiral β'-amino-α,β-enones, in seven steps, from an α,β unsaturated ester has been described. The use of a Horner-Wadsworth-Emmons reaction as a key step for generating the β'-amino-α,β-enones, permits access to a range of substrates under mild conditions and in moderate to high yield.
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Chiral β-aryl-α,β-unsaturated amino alcohols were synthesized via a Pd-catalyzed asymmetric allylic amination of 4-aryl-1,3-dioxolan-2-one using planar chiral 1,2-disubstituted ferrocene-based phosphinooxazolines as ligands. Under the optimized reaction conditions, a series of substrates were examined and the products were obtained in good to excellent yields (up to 92%) and enantioselectivitie...
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The first organocatalytic double Michael cascade reaction between unsaturated ketones and unsaturated pyrazolones has been developed which provides spiropyrazolone core structures containing two interval or three consecutive stereogenic centers with excellent diastereo- (>20:1) and enantioselectivities (up to 99% ee). Moreover, a pair of enantiomers and can be achieved via different catalysts.
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ژورنال
عنوان ژورنال: Organic & Biomolecular Chemistry
سال: 2015
ISSN: 1477-0520,1477-0539
DOI: 10.1039/c5ob00364d