Influence of Lewis Acids on the Cycloaddition Reactions of Cyano- and Carbomethoxy-Substituted Olefins

1994 ◽  
Vol 59 (18) ◽  
pp. 5424-5435 ◽  
Author(s):  
Warunee Srisiri ◽  
Anne Buyle Padias ◽  
H. K. Hall
Keyword(s):  
Lewis Acids ◽  
Cycloaddition Reactions

Efficient Catalytic Effects of Lewis Acids in the 1,3-Dipolar Cycloaddition Reactions of Carbonyl Ylides with Imines

2005 ◽  
Vol 70 (26) ◽  
pp. 10782-10791 ◽  
Author(s):  
Hiroyuki Suga ◽  
Yasutaka Ebiura ◽  
Kazuaki Fukushima ◽  
Akikazu Kakehi ◽  
Toshihide Baba
Keyword(s):  
Lewis Acids ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Catalytic Effects

Gold-catalyzed generation of vinylthionium ions and the development of an organocatalytic, asymmetric (4+3)-cycloaddition reaction

2017 ◽  
Author(s):  
◽  
Michael Topinka
Keyword(s):  
Amino Alcohol ◽  
Good Yield ◽  
Lewis Acids ◽  
Cycloaddition Reaction ◽  
Unsaturated Ester ◽  
Cycloaddition Reactions ◽  
University Of Missouri ◽  
Considerable Problem ◽  
The University ◽  
Substituted Furans

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] An allylic benzoate ester was prepared and used as a progenitor of vinylthionium ions for (4+3)-cycloaddition reactions. The chemistry was limited to 2-substituted and 2,5-disubstituted furans. In the case of 2-substituted furans, only Friedel-Crafts alkylation products were procured. In the case of 2,5-disubstituted furans, (4+3)-cycloaddition products were furnished in good yield. A catalytic, asymmetric variant using 2,5-dialkylfurans and chiral acids to procure cycloaddition products was unsuccessful. There was an opportunity to overcome the Friedel-Crafts alkylation problem that arose in a gold-catalyzed cycloaddition project. A sulfur-substituted unsaturated ester and alcohol were prepared, but silyl migration was a considerable problem upon activation by various agents. The problem of silyl migration was circumvented, but the target aldehyde was unreactive toward dienes in the presence of various Lewis acids. In further pursuit of an asymmetric (4+3)-cycloaddition reaction, 2-substituted furans were reacted with 2-tosyloxycyclopentanone in the presence of K2HPO4/H2O in perfluorobenzene as solvent and 30 mol% of an amino alcohol catalyst developed by David MacMillan. Enantioselectivities were modest for 2-alkylfurans and excellent for 2-arylchalcogenofurans (90% ee). 3-Substituted furans also work in this process.

Highly Enantioselective 1,3-Dipolar Cycloaddition Reactions of 2-Benzopyrylium-4-olate Catalyzed by Chiral Lewis Acids

2002 ◽  
Vol 124 (50) ◽  
pp. 14836-14837 ◽  
Author(s):  
Hiroyuki Suga ◽  
Kei Inoue ◽  
Shuichi Inoue ◽  
Akikazu Kakehi
Keyword(s):  
Lewis Acids ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions

scholarly journals Reversal of reaction type selectivity by Lewis acid coordination: the ortho photocycloaddition of 1- and 2-naphthaldehyde

2019 ◽  
Vol 10 (37) ◽  
pp. 8566-8570 ◽  
Author(s):  
Simone Stegbauer ◽  
Noah Jeremias ◽  
Christian Jandl ◽  
Thorsten Bach
Keyword(s):  
Visible Light ◽  
Lewis Acid ◽  
Visible Light Irradiation ◽  
Lewis Acids ◽  
Light Irradiation ◽  
Cycloaddition Reactions ◽  
Reaction Type ◽  
Photochemical Behaviour

Lewis acids, such as AlBr3, completely alter the photochemical behaviour of naphthaldehydes. Instead of typical carbonyl photochemistry, the aldehydes undergo cycloaddition reactions at the arene core upon visible-light irradiation.

Preparation of MOF catalysts and simultaneously modulated metal nodes and ligands via a one-pot method for optimizing cycloaddition reactions

2020 ◽  
Vol 44 (23) ◽  
pp. 9611-9615
Author(s):  
Peng Wang ◽  
Sha Wang ◽  
Wenlei Zhang ◽  
Xiaohan Li ◽  
Zhida Gu ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Cycloaddition Reactions ◽  
Bronsted Acids ◽  
One Pot

MOFs were adjusted with metal nodes and ligands to endow them with Lewis acids and Brønsted acids for enhanced cycloaddition reactions.

Lewis acid mediated [3+2] and [3+3] annulations of azomethine imine with donor-acceptor cyclopropanes

Synthesis ◽  
2021 ◽  
Author(s):  
Raghuramaiah Mandadapu ◽  
Amol Satish Dehade ◽  
Shrikant Abhiman Shete ◽  
Mark Montgomery ◽  
Vikas Sikervar ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Cycloaddition Reactions ◽  
Azomethine Imine ◽  
Donor Acceptor ◽  
Azomethine Imines

The [3+2] and [3+3] regioselective cycloaddition reactions of azomethine imines with activated cyclopropanes have been developed using two different Lewis acids. Scandium (III) triflate serves as a catalyst for the [3+2] cycloaddition reactions of azomethine imines with cyclopropanes to form tetrahydropyrazolone derivatives and tricyclic tetrahydrofuran derivatives in moderate yields. In complementary to this, novel [3+3] cycloaddition reactions of azomethine imine with activated cyclopropanes have been developed using EtAlCl2 as a Lewis acid to form hexahydropyridazinone derivatives in high regioselectivity.

Asymmetric [3+3] Cycloaddition for Heterocycle Synthesis

Synlett ◽  
2017 ◽  
Vol 28 (14) ◽  
pp. 1695-1706 ◽  
Author(s):  
Yongming Deng ◽  
Qing-Qing Cheng ◽  
Michael Doyle
Keyword(s):  
Transition Metal ◽  
Lewis Acids ◽  
Heterocyclic Compounds ◽  
Cycloaddition Reaction ◽  
Membered Ring ◽  
Transition Metal Catalysts ◽  
Transition Metal Catalysis ◽  
Cycloaddition Reactions ◽  
Metal Catalysis ◽  
Phosphoric Acids

Asymmetric syntheses of six-membered ring heterocycles are important research targets not only in synthetic organic chemistry but also in pharmaceuticals. The [3+3]-cycloaddition methodology is a complementary strategy to [4+2] cycloaddition for the synthesis of heterocyclic compounds. Recent progress in [3+3]-cycloaddition processes provide powerful asymmetric methodologies for the construction of six-membered ring heterocycles with one to three heteroatoms in the ring. In this account, synthetic efforts during the past five years toward the synthesis of enantioenriched six-membered ring heterocycles through asymmetric [3+3] cycloaddition are reported. Asymmetric organocatalysis uses chiral amines, thioureas, phosphoric acids, or NHC catalysis to achieve high enantiocontrol. Transition-metal catalysts used as chiral Lewis acids to activate a dipolar species is an alternative approach. The most recent advance, chiral transition-metal-catalyzed reactions of enoldiazo compounds, has contributed toward the versatile and highly selective synthesis of six-membered heterocyclic compounds.1 Introduction2 Asymmetric Formal [3+3]-Cycloaddition Reactions by Organo­catalysis2.1 By Amino-Catalysis2.2 By N-Heterocyclic Carbenes2.3 By Bifunctional Tertiary Amine-thioureas2.4 By Chiral Phosphoric Acids3 Asymmetric Formal [3+3]-Cycloaddition Reactions by Transition-Metal Catalysis3.1 Copper Catalysis3.2 Other Transition-Metal Catalysis4 Asymmetric [3+3]-Cycloaddition Reactions of Enoldiazo Compounds4.1 Asymmetric [3+3]-Cycloaddition Reactions of Nitrones with Electrophilic Metallo-enolcarbene Intermediates4.2 Dearomatization in Asymmetric [3+3]-Cycloaddition Reactions of Enoldiazoacetates4.3 Asymmetric Stepwise [3+3]-Cycloaddition Reaction of Enoldiazoacetates with Hydrazones5 Summary and Outlook

scholarly journals Highly Enantioselective 1,3-Dipolar Cycloaddition Reactions of 2-Benzopyrylium-4-olate Catalyzed by Chiral Lewis Acids.

ChemInform ◽  
2003 ◽  
Vol 34 (17) ◽  
Author(s):  
Hiroyuki Suga ◽  
Kei Inoue ◽  
Shuichi Inoue ◽  
Akikazu Kakehi
Keyword(s):  
Lewis Acids ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions
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