Asymmetric Synthesis of 2,3-Dihydrofurans via Squaramide Catalyzed Michael-Alkylation Reaction

2021 ◽  
Vol 19 ◽  
Author(s):  
Zhi-Wei Ma ◽  
Chuan-Chuan Wang ◽  
Xiao-Pei Chen ◽  
Bin Sun ◽  
Jing-Chao Tao ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Catalysis ◽  
Tertiary Amine ◽  
Alkylation Reaction

Abstract: Asymmetric Catalysis, Dihydrofuran, Michael-Alkylation Reaction, Tertiary Amine-Squaramide, Organocatalysis, α-Bromonitroalkene

Carbonyl catalysis enables a biomimetic asymmetric Mannich reaction

Science ◽  
2018 ◽  
Vol 360 (6396) ◽  
pp. 1438-1442 ◽  
Author(s):  
Jianfeng Chen ◽  
Xing Gong ◽  
Jianyu Li ◽  
Yingkun Li ◽  
Jiguo Ma ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
High Activity ◽  
Asymmetric Catalysis ◽  
Carbonyl Group ◽  
Mannich Reaction ◽  
Primary Amine ◽  
Chiral Amines ◽  
Carbonyl Groups ◽  
Diphenylphosphinyl Imines

Chiral amines are widely used as catalysts in asymmetric synthesis to activate carbonyl groups for α-functionalization. Carbonyl catalysis reverses that strategy by using a carbonyl group to activate a primary amine. Inspired by biological carbonyl catalysis, which is exemplified by reactions of pyridoxal-dependent enzymes, we developed an N-quaternized pyridoxal catalyst for the asymmetric Mannich reaction of glycinate with aryl N-diphenylphosphinyl imines. The catalyst exhibits high activity and stereoselectivity, likely enabled by enzyme-like cooperative bifunctional activation of the substrates. Our work demonstrates the catalytic utility of the pyridoxal moiety in asymmetric catalysis.

A Concise and Modular Three-Step Synthesis of (S)-Verapamil using an Enantioselective Rhodium-Catalyzed Allylic Alkylation Reaction

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2185-2189 ◽  
Author(s):  
P. Andrew Evans ◽  
Mai-Jan Tom ◽  
Ben W. H. Turnbull
Keyword(s):  
Calcium Channel ◽  
Asymmetric Synthesis ◽  
Channel Blocker ◽  
Alkylation Reaction ◽  
Allylic Alkylation ◽  
Efficient Synthesis ◽  
Terminal Olefin ◽  
Bioactive Agents ◽  
Quaternary Stereocenter ◽  
Modular Nature

A concise and modular asymmetric synthesis of the calcium channel blocker (S)-verapamil is described. This approach employs an enantioselective rhodium-catalyzed allylic alkylation reaction between an α-isopropyl-substituted benzylic nitrile and allyl benzoate to construct the challenging acyclic quaternary stereocenter. The terminal olefin then serves as a convenient synthetic handle for a hydroamination to introduce the phenethylamine moiety, furnishing (S)-verapamil in three steps and 55% overall yield, thus providing the most efficient synthesis of this important pharmaceutical reported to date. Furthermore, given the modular nature of the synthesis, it can be readily modified to prepare structurally related bioactive agents.

Catalytic Asymmetric Synthesis of P-Stereogenic Phosphines: Beyond Precious Metals

Synlett ◽  
2020 ◽  
Author(s):  
David S. Glueck
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Catalysis ◽  
Palladium Catalysts ◽  
Precious Metals ◽  
Synthetic Methods ◽  
Secondary Phosphine ◽  
Phosphine Oxides ◽  
Chiral Epoxides ◽  
Earth Abundant ◽  
Limonene Oxide

AbstractMetal-catalyzed asymmetric synthesis of P-stereogenic phosphines is a potentially useful approach to a class of chiral ligands with valuable applications in asymmetric catalysis. We introduced this idea with chiral platinum and palladium catalysts, exploiting rapid pyramidal inversion in diastereomeric metal–phosphido complexes (ML*(PRR′)) to control phosphorus stereochemistry. This Account summarizes our attempts to develop related synthetic methods using earth-abundant metals, especially copper, in which weaker metal–ligand bonds and faster substitution processes were expected to result in more active catalysts. Indeed, precious metals were not required. Without any transition metals at all, we exploited related P-epimerization processes to prepare enantiomerically pure phosphiranes and secondary phosphine oxides (SPOs) from commercially available chiral epoxides.1 Introduction2 Copper-Catalyzed Phosphine Alkylation3 Copper-Catalyzed Tandem Phosphine Alkylation/Arylation4 Nickel-Catalyzed Phosphine Alkylation5 Proton-Mediated P-Epimerization in Synthesis of Chiral Phosphiranes6 Diastereoselective Synthesis of P-Stereogenic Secondary Phosphine Oxides (SPOs) from (+)-Limonene Oxide7 Conclusions

scholarly journals Asymmetric reactions in continuous flow

2009 ◽  
Vol 5 ◽  
Author(s):  
Xiao Yin Mak ◽  
Paola Laurino ◽  
Peter H Seeberger
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Catalysis ◽  
Continuous Flow ◽  
Asymmetric Reactions ◽  
Heterogeneous Asymmetric Catalysis

An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

ChemInform Abstract: Asymmetric Synthesis of (+)- and (-)-Coniines and (-)-Sedamine by Diastereoselective Alkylation Reaction of Ethoxypiperidinone.

ChemInform ◽  
2010 ◽  
Vol 22 (9) ◽  
pp. no-no
Author(s):  
T. KIGUCHI ◽  
Y. NAKAZONO ◽  
S. KOTERA ◽  
I. NINOMIYA ◽  
T. NAITO
Keyword(s):  
Asymmetric Synthesis ◽  
Alkylation Reaction

Asymmetric Synthesis of Dihydrofurans via Organocatalytic Domino Michael-Alkylation Reaction

2015 ◽  
Vol 357 (6) ◽  
pp. 1305-1310 ◽  
Author(s):  
Juhua Feng ◽  
Lili Lin ◽  
Kunru Yu ◽  
Xiaohua Liu ◽  
Xiaoming Feng
Keyword(s):  
Asymmetric Synthesis ◽  
Alkylation Reaction

ChemInform Abstract: Recyclable Tertiary Amine Modified Diarylprolinol Ether as Aminocatalyst for the Sequential Asymmetric Synthesis of Functionalized Cyclohexanes and Chromenes.

ChemInform ◽  
2012 ◽  
Vol 43 (8) ◽  
pp. no-no
Author(s):  
Hao Shen ◽  
Ke-Fang Yang ◽  
Zi-Hui Shi ◽  
Jian-Xiong Jiang ◽  
Guo-Qiao Lai ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Tertiary Amine

Ephedrines as Chiral Auxiliaries in Enantioselective Alkylation Reactions of Acyl Ephedrine Amides and Esters: A Review

2018 ◽  
Vol 15 (1) ◽  
pp. 38-83 ◽  
Author(s):  
Alejandro Cruz ◽  
Itzia I. Padilla-Martínez ◽  
Maria E. Bautista-Ramirez
Keyword(s):  
Asymmetric Synthesis ◽  
Bond Formation ◽  
Alkyl Halides ◽  
Aldol Reactions ◽  
Alkylation Reaction ◽  
Chiral Auxiliaries ◽  
Asymmetric Alkylation ◽  
Chiral Compounds ◽  
High Yields ◽  
Alkylation Reactions

Background: In modern chemistry, the asymmetric synthesis for the preparation of high purity chiral compounds to be used as pharmaceuticals or additives in foods have been of capital importance. Chiral auxiliary reagents are used to control the stereochemistry of the reaction in the generation of new chiral compounds, in this context, Ephedra compounds (ephedrines and pseudoephedrines) and some of their derivatives have been broadly used as chiral ligands in catalysis or chiral inductors in asymmetric synthesis. Objective: This review focuses on recent progress in the use of ephedra compounds and their N-substituted derivatives as chiral auxiliaries in the area of asymmetric synthesis, via the alkylation reaction of the enolates derived from their corresponding N-Acyl or O-Acyl derivatives, in the C-C bond formation. Conclusion: A vast amount of work has been done about the use of ephedra compounds in asymmetric synthesis area, in general, it was found that pseudoephedrines are much more effective than ephedrines and are preferred as chiral auxiliaries in the asymmetric alkylation of the corresponding N-acyl amides or O-Acyl esters. Alkylation with alkyl halides requires the use of more than 4 equivalents of LiCl to accelerate the alkylation rate and to complete the reaction without effecting the diastereoselectivity of the process. In contrast, the use of secondary alkyl halides was found to make the reaction very slow. Furthermore, a lot of work about the alkylation reaction in the opening of epoxides and aziridines, aldolic condensation, Manich reaction, addition of nucleophiles to α,β-unsaturated ephedrine amides and Michael additions have been demonstrated to be effective in the C-C bond formation. The aldol reaction of chiral enolates, proceeds with decreasing yields and enantioselectivities as the steric demand of the α-R of ephedrine amides and the size of carbonyl compound increase. In addition, the use of branched groups on N,N-disubstituted norephedrine esters is highly recommended in the aldol reactions of aromatic and aliphatic aldehydes.In the case of N-Acyl or O-Acyl ephedrines supported on polymers, the reaction proceed with good enantioselectivities but low yields, the enantioselectivities are goods but the yields are low. In general, the removal step of the auxiliary proceeds with low to high yields but without epimerization.

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