188446-25-5Relevant academic research and scientific papers
A Synthetic Route to β-Hydroxytyrosine-Derived Tetramic Acids: Total Synthesis of the Fungal Metabolite F-14329
Bruckner, Sebastian,Haase, Robert G.,Schobert, Rainer
supporting information, p. 5692 - 5695 (2017/04/28)
3-Acyltetramic acids derived from β-hydroxytyrosine are synthetically challenging. The first route to this structural motif, based upon a condensation between a Meldrum's acid conjugate bearing the acyl side chain, and a β-hydroxytyrosinate, N-protected by an ortho-nitrobenzyl group is presented. This group enables the Dieckmann cyclization of the resulting N-(β-ketoacyl)amino ester, after which it can be removed photolytically without compromising the delicate 3′-hydroxy group. This strategy was applied to the first total synthesis of the fungal metabolite F-14329 (1).
Diastereo- and enantioselective hydrogenation of α-amino-β-keto ester hydrochlorides catalyzed by an iridium complex with MeO-BIPHEP and NaBArF: Catalytic cycle and five-membered chelation mechanism of asymmetric hydrogenation
Maeda, Tsukuru,Makino, Kazuishi,Iwasaki, Masamichi,Hamada, Yasumasa
supporting information; experimental part, p. 11954 - 11962 (2011/01/12)
The development of Ir-catalyzed asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides is described. This reaction proceeds through a dynamic kinetic resolution to produce anti-β-hydroxy- α-amino acid esters in a high diastereo- and enantioselective manner. Mechanistic studies have revealed that this unique asymmetric hydrogenation proceeds through reduction of the ketone moiety via the five-membered transition state involving the chelation between the oxygen of the ketone and the nitrogen of the amine function. The relationship studies between the hydrogen pressure and the stereoselectivity have disclosed two mechanisms dependent on hydrogen pressure. Under low hydrogen pressure (15 atm), the reaction rate proportionally increased with the hydrogen pressure. However, under the high hydrogen conditions, the reaction rate exponentially accelerated along with the increasing hydrogen pressure, which suggests the participation of two or more of hydrogen atoms. Apply some pressure: The Ir-catalyzed asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides proceeds through a dynamic kinetic resolution to produce anti-β-hydroxy-α-amino acid esters in a high diastereo- and enantioselective manner (see scheme). Mechanistic studies revealed that this unique asymmetric hydrogenation proceeds through reduction of the ketone moiety via the five-membered transition state.
Enantio- and diastereoselective hydrogenation via dynamic kinetic resolution by a cationic iridium complex in the synthesis of β-hydroxy-α-amino acid esters
Makino, Kazuishi,Iwasaki, Masamichi,Hamada, Yasumasa
, p. 4573 - 4576 (2007/10/03)
Anti-selective asymmetric hydrogenation of α-amino-β-keto esters via dynamic kinetic resolution under low hydrogen pressure has been achieved by an easily-handled cationic iridium complex with tetrakis[3,5- bis(trifluoromethyl)phenyl]borate (BARF) as a co
Synthesis of (9R,12S)- and (9S,12S)-cycloisodityrosine and their N-methyl derivatives
Boger, Dale L.,Zhou, Jiacheng,Borzilleri, Robert M.,Nukui, Seiji,Castle, Steven L.
, p. 2054 - 2069 (2007/10/03)
Full details of the synthesis of (9R,12S)- and (9S,12S)-cycloisodityrosine and their N-methyl derivatives are detailed based on an intramolecular nucleophilic aromatic substitution reaction for formation of the key biaryl ether with 14-membered ring macrocyclization. Their comparison with prior samples and the documentation of a facile C9 epimerization within the natural 9S series are described.
