Asymmetric synthesis of 9-alkyl tetrahydroxanthenones via tandem asymmetric Michael/cyclization promoted by chiral phosphoric acid

2021 ◽  
Author(s):  
Yu-Qi Gao ◽  
Yi Hou ◽  
Junhan Chen ◽  
Yanxia Zhen ◽  
Dongyang Xu ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Dicarbonyl Compounds ◽  
Asymmetric Michael Addition ◽  
Chiral Phosphoric Acid

A tandem asymmetric Michael-addition/cyclization of cyclic 1,3-dicarbonyl compounds to β,γ-unsaturated α-ketoesters catalyzed by chiral phosphoric acid is presented.

Asymmetric Synthesis of t-Butyl 3-Alkyl-oxindole-3-carboxylates via Chiral Phosphoric Acid Catalyzed Desymmetrization of Di-t-butyl 2-Alkyl-2-(2-aminophenyl)malonates

Heterocycles ◽  
2019 ◽  
Vol 99 (2) ◽  
pp. 1398
Author(s):  
Takaaki Sumiyoshi ◽  
Kyoji Ishida ◽  
Masahiro Shimizu ◽  
Yu-suke Yamai ◽  
Itaru Natsutani ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Chiral Phosphoric Acid ◽  
Acid Catalyzed

Organocatalytic asymmetric synthesis of benzazepinoindole derivatives with trifluoromethylated quaternary stereocenters by chiral phosphoric acid catalysts

2018 ◽  
Vol 16 (8) ◽  
pp. 1367-1374 ◽  
Author(s):  
Abdul Rahman ◽  
En Xie ◽  
Xufeng Lin
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Acid Catalysts ◽  
Chiral Phosphoric Acid ◽  
Quaternary Stereocenters

An enantioselective aza-Friedel–Crafts reaction of trifluoromethyl dihydrobenzoazepinoindoles with pyrroles or indoles catalyzed by a chiral spirocyclic phosphoric acid was developed.

Direct enantioselective Mannich reactions of α-azido cyclic ketones: asymmetric construction of chiral azides possessing an α-quaternary stereocenter

2020 ◽  
Vol 56 (1) ◽  
pp. 98-101 ◽  
Author(s):  
Xueqian Ye ◽  
Yongkai Pan ◽  
Xiaoyu Yang
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Cyclic Ketones ◽  
Mannich Reactions ◽  
Chiral Phosphoric Acid ◽  
Quaternary Stereocenter

Herein, we report the asymmetric synthesis of chiral azides possessing an α-quaternary stereocenter via chiral phosphoric acid catalysed direct enantioselective Mannich reactions of α-azido cyclic ketones with aldimines.

scholarly journals A chiral phosphoric acid catalyst for asymmetric construction of 1,3-dioxanes

2015 ◽  
Vol 51 (58) ◽  
pp. 11693-11696 ◽  
Author(s):  
Akira Matsumoto ◽  
Keisuke Asano ◽  
Seijiro Matsubara
Keyword(s):  
Phosphoric Acid ◽  
Michael Addition ◽  
Acid Catalyst ◽  
Chiral Phosphoric Acid

A chiral phosphoric acid catalyst enabled enantioselective 1,3-dioxane construction, useful for polyketide motif synthesis, via a hemiacetalization/intramolecular oxy-Michael addition cascade.

Chiral Ruthenium PNNP Complexes of Non-Enolized 1,3-Dicarbonyl Compounds:  Acidity and Involvement in Asymmetric Michael Addition

2006 ◽  
Vol 25 (13) ◽  
pp. 3108-3110 ◽  
Author(s):  
Martin Althaus ◽  
Cristina Bonaccorsi ◽  
Antonio Mezzetti ◽  
Francesco Santoro
Keyword(s):  
Michael Addition ◽  
Dicarbonyl Compounds ◽  
Asymmetric Michael Addition

Acidic Ruthenium PNNP Complexes of Non-enolized 1,3-Dicarbonyl Compounds as Catalysts for Asymmetric Michael Addition

2008 ◽  
Vol 27 (15) ◽  
pp. 3866-3878 ◽  
Author(s):  
Francesco Santoro ◽  
Martin Althaus ◽  
Cristina Bonaccorsi ◽  
Sebastian Gischig ◽  
Antonio Mezzetti
Keyword(s):  
Michael Addition ◽  
Dicarbonyl Compounds ◽  
Asymmetric Michael Addition

scholarly journals Efficient Asymmetric Synthesis of Prostaglandin E1

2007 ◽  
Vol 62 (4) ◽  
pp. 556-560 ◽  
Author(s):  
Jae-Chul Jung ◽  
Oee-Sook Park
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Prostaglandin E1 ◽  
Simple Synthesis ◽  
High Yield ◽  
Prostaglandin E ◽  
Magnesium Bromide ◽  
One Pot ◽  
Asymmetric Michael Addition ◽  
Key Steps

A simple synthesis of prostaglandin E1 (PGE1) is described. The key steps are an asymmetric Michael addition to establish the desired (R)-configurations at C8 and C12 of the 2- (trimethylsilyl)ethoxymethyl- (SEM) protected PGE1 and its one-pot deprotection with magnesium bromide in high yield. This method is potentially useful for the preparation of other modified prostaglandins.

scholarly journals Asymmetric Michael addition using sugar derived organocatalysts

2017 ◽  
Vol 17 (4) ◽  
pp. 182-196
Author(s):  
P.B. Lalthanpuii ◽  
C. Lalhriatpuia ◽  
K. Vanlaldinpuia
Keyword(s):  
Molecular Weight ◽  
Asymmetric Synthesis ◽  
Present Article ◽  
Asymmetric Catalysis ◽  
Michael Addition ◽  
Metal Contamination ◽  
Low Molecular Weight ◽  
Asymmetric Transformations ◽  
Asymmetric Michael Addition ◽  
Different Types

Sugars are low-molecular-weight carbohydrates which consist of polyhydroxyl and carbonyl (aldehyde or ketone) functional groups. Different types of compounds derived from sugars have been used extensively as powerful and effective catalysts for asymmetric synthesis. They are readily available at a reasonable price, easily prepared, no metal contamination and are inert towards moisture and air. They are highly functionalized and have well defined stereogenic centres. Most of them are employed as chiral ligands in metal based asymmetric catalysis and are used for various asymmetric transformations. Different compounds derived from sugars have also been used recently as organocatalysts for asymmetric synthesis. The present article provides some of the organocatalysts used for asymmetric synthesis.

Asymmetric synthesis of atropisomeric pyrazole via an enantioselective reaction of azonaphthalene with pyrazolone

2019 ◽  
Vol 55 (84) ◽  
pp. 12715-12718 ◽  
Author(s):  
Huijun Yuan ◽  
Yao Li ◽  
Hanhui Zhao ◽  
Zhihong Yang ◽  
Xin Li ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Pyrazole Derivatives ◽  
Asymmetric Reaction ◽  
Chiral Phosphoric Acid ◽  
Wide Range ◽  
Axially Chiral ◽  
Enantioselective Reaction ◽  
Catalytic Asymmetric

The first catalytic asymmetric reaction of azonaphthalene with pyrazolone has been established. A wide range of axially chiral pyrazole derivatives have been achieved in good yields (68–99%) with excellent enantioselectivities (83–98% ee) by utilizing chiral phosphoric acid as a catalyst.

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