- Catalytic Asymmetric Synthesis of Unprotected β2-Amino Acids
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We report here a scalable, catalytic one-pot approach to enantiopure and unmodified β2-amino acids. A newly developed confined imidodiphosphorimidate (IDPi) catalyzes a broadly applicable reaction of diverse bis-silyl ketene acetals with a silylated aminomethyl ether, followed by hydrolytic workup, to give free β2-amino acids in high yields, purity, and enantioselectivity. Importantly, both aromatic and aliphatic β2-amino acids can be obtained using this method. Mechanistic studies are consistent with the aminomethylation to proceed via silylium-based asymmetric counteranion-directed catalysis (Si-ACDC) and a transition state to explain the enantioselectivity is suggested on the basis of density functional theory calculation.
- Zhu, Chendan,Mandrelli, Francesca,Zhou, Hui,Maji, Rajat,List, Benjamin
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supporting information
p. 3312 - 3317
(2021/04/07)
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- A new enantioselective synthesis of β-amino acids
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Enantioselective hydrogenation of some α,β-unsaturated nitriles and their corresponding methyl esters bearing a phthalimidomethyl substituent at the α-carbon using Rh-DuPHOS catalysts afforded β-amino acid precursors with modest e.e.s of up to 48%. Hydrogenation of the α,β-unsaturated methyl esters using a Ru-BINAP catalyst gave higher e.e.s of up to 84%. Method development for the determination of the enantiomeric excesses of these derivatives using chiral HPLC is also reported.
- Saylik, Dilek,Campi, Eva M.,Donohue, Andrew C.,Jackson,Robinson, Andrea J.
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p. 657 - 667
(2007/10/03)
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- Chartreusin derivatives and salts thereof
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This invention relates to a novel chartreusin derivative of the general formula (I): STR1 and a salt thereof. This chartreusin derivative and a salt thereof have an excellent antitumor activity, which is exhibited even when the site of cancer inoculation and the site of drug administration are different. This invention further relates to a antitumorous composition containing the above-mentioned compound as active ingredient. This invention furthermore relates to a process for producing the above-mentioned chartreusin derivative or salt thereof.
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