Asymmetric α‐Hydroxylation of β‐Indanone Esters and β‐Indanone Amides Catalyzed by C‐2′ Substituted Cinchona Alkaloid Derivatives

Abstract

Theh ighly catalytic asymmetric a-hydroxylation of b-indanone esters and b-indanone amides using peroxide as the oxidant was realized with an ew C-2' substituted Cinchona alkaloid derivatives. Thet wo enantiomers of a-hydroxy-b-indanone esters could be obtained by simply changing the oxidant. This protocola llows ac onvenient access to the corresponding a-hydroxy-b-indanone esters and a-hydroxy-b-indanone amides with up to 99% yield and 98% ee.

C5’‐Nitrated Cinchona Catalysts for Asymmetric Michael Addition Reaction

“…In 2011, Stephen et al synthesized the same compound using fuming nitric acid at À 10 °C. [17] Later Deng [20] and Meng [21] independently followed Stephen's method to prepare Q1.…”

“…[20] Meng et al investigated the α-hydroxylation of a β-keto ester (Scheme 1 (2)) catalyzed by Q1, which showed little catalytic activity. [21] Cinchona catalysts substituted with the C5'nitro group may have unique catalytic activity owing to the bulky, electron withdrawing features of this group. Therefore, herein, we attempt the synthesis of C5'-nitrated cinchona alkaloids and focus on the catalytic activity of C5' nitrated catalysts in enantioselective Michael addition reactions.…”

“…Meng et al. investigated the α‐hydroxylation of a β‐keto ester (Scheme 1 (2)) catalyzed by Q1 , which showed little catalytic activity [21] . Cinchona catalysts substituted with the C5’‐nitro group may have unique catalytic activity owing to the bulky, electron withdrawing features of this group.…”

Nucleophilic Halogenation of Cyclic Nitronates: A General Access to 3-Halo-1,2-Oxazines

“…These products possess promising biological activities and are important building blocks for cross-coupling and S N Ar reactions (Scheme ). In the recent years, this methodology has been extensively exploited in the synthesis of pharmaceutically relevant compounds (such as 2-amino-substituted nitrogen heterocycles), organocatalysts, and optic materials . Nucleophilic halogenation of N -oxides has many advantages over conventional methods used for the incorporation of halogens onto heterocycles.…”

A Series of Cinchona-Derived N-Oxide Phase-Transfer Catalysts: Application to the Photo-Organocatalytic Enantioselective α-Hydroxylation of β-Dicarbonyl Compounds

“…On the other hand, the optically active α-hydroxy-β-dicarbonyl moiety is an intriguing structural motif in a variety of natural products and pharmaceuticals (Scheme ). Asymmetric catalysis by chiral metal complexes and organocatalysts were developed rapidly in the last two decades. , Along these lines, various oxidants, such as N -sulfonyloxaziridines, peroxides, dimethyldioxirane, and nitrosobenzene, have been utilized. However, molecular oxygen as the oxygen source has rarely been reported. Considering an economical as well as environmental viewpoint, the use of molecular oxygen as the oxygen source would undoubtedly make it an ideal candidate in organic synthesis, especially in the field of asymmetric catalysis …”