99853-87-9Relevant academic research and scientific papers
Novel and practical asymmetric synthesis of β2,3-amino esters using asymmetric Michael addition of chiral amine
Ozeki, Minoru,Egawa, Honoka,Takano, Toshiki,Mizutani, Hideki,Yasuda, Narumi,Arimitsu, Kenji,Kajimoto, Tetsuya,Hosoi, Shinzo,Iwasaki, Hiroki,Kojima, Naoto,Node, Manabu,Yamashita, Masayuki
, p. 2014 - 2021 (2017)
A practical method for the synthesis of chiral β2,3-amino esters having various substituents was developed, which is characterized by an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. We found that a highly face-selective protonation occurred by the quick addition of water to the enolate intermediate derived from the Michael addition reaction to afford N-protected β2,3-amino esters in moderate to excellent yields. This finding was made possible by the facile preparation of geometrically pure trisubstituted (E)-α,β-unsaturated esters, which was established recently by our group. The subsequent deprotection of the amino group in the Michael adduct by using N-iodosuccinimide (NIS) efficiently provided β2,3-amino esters having various substituents.
Enantioselective palladium(0)-catalyzed nazarov-type cyclization
Kitamura, Kei,Shimada, Naoyuki,Stewart, Craig,Atesin, Abdurrahman C.,Atein, Tülay A.,Tius, Marcus A.
supporting information, p. 6288 - 6291 (2015/05/20)
A Pd0-catalyzed asymmetric Nazarov-type cyclization is described. The optimized ligand for the reaction incorporates a weakly coordinating pyridine ring into a TADDOL-derived phosphoramidite (TADDOL=α,α,α,α-tetraaryl-1,3-dioxolane-4,5-dimethanol). The reaction leads to the formation of cyclopentenones as single diastereoisomers that incorporate two contiguous asymmetric centers, one tertiary and one an all-carbon-atom quaternary stereocenter, in high yield and optical purity. It is noteworthy that the reaction does not require that substrates should be activated by aryl substituents.
Asymmetric hydrogenation of α,β-unsaturated carboxylic esters with chiral iridium N,P ligand complexes
Woodmansee, David H.,Mueller, Marc-Andre,Troendlin, Lars,Hoermann, Esther,Pfaltz, Andreas
supporting information, p. 13780 - 13786 (2013/01/15)
Enantioselective conjugate reduction of a wide range of α,β-unsaturated carboxylic esters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. α,β-Unsaturated carboxylic esters substituted at the α position are less problematic substrates than originally anticipated and in some cases α-substituted substrates actually reacted with higher enantioselectivity than their β-substituted analogues. The resulting saturated esters with a stereogenic center in the α or β position were obtained in high enantiomeric purity. Copyright
