Double axially chiral bisphosphorylimides as novel Brønsted acids in asymmetric three-component Mannich reaction

Die katalytische asymmetrische Acetalisierung

“…11 und 12). [12] Wir konzentrierten uns nun auf unsymmetrische Substituenten R und testeten den o-Isopropylphenylsubstituierten Katalysator 7 h, der die Enantioselektivität weiter verbesserte (Tabelle 1, Nr. 13).…”

Organocatalyzed Asymmetric Friedel‐Crafts Reactions: An Update

“…The highly asymmetric AF‐CA transformation of indoles and trifluoropyruvate mediated by a C3‐symmetric cinchonine‐squaramide was developed in 2012 . A varied range of trifluoromethylated indoles have been made in high yields (99 %) and ee value (up to >99 %) . Based on the optimized condition, a range of indoles have been considered to test the substrate range.…”

“…It is significant that substitution on the pyrrole ring had slight influence on the ee . For instance, the indole having a Me substituent at the 2‐position 14 g reacted with ethyl trifluoropyruvate to make the expected compound in 91 % enantioselectivity …”

“…Moreover, analogous high results have been accomplished for indoles having an electron‐deficient substituent on the phenyl ring compared to derivatives having an electron‐withdrawing substituent in terms of ee value and yield. Regarding the indole containing the CO 2 Me substituent at the 5‐position, it reacted fine with methyl trifluoropyruvate, and has been provided with 83 % enantioselectivity (Scheme , Table ) …”

Screening Approach for Chiral Separation of β‐Aminoketones by HPLC on Various Polysaccharide‐Based Chiral Stationary Phases

“…4 It is one of the most important carboncarbon bond formation reactions in organic synthesis, [5][6][7][8][9][10][11][12][13][14] in which an aminomethyl group is introduced to the α position of a carbonyl function. 3,15 In the classical condensation, a single carbon atom is attached to an active methylene or methine group, using formaldehyde and an amine, to generate β-amino carbonyl compounds (Mannich bases), which are highly useful chiral building blocks 16,17 and important intermediates for the synthesis of various pharmaceutical and natural product synthesis including β-amino alcohols, β-amino acids, and β-lactams. 18 The reaction has been extensively studied by organic chemists and has been the subject of numerous reviews.…”