The Application of 1,2-Oxazinanes as Chiral Cyclic Weinreb Amide-type Auxiliaries Leading to a Three Component One-Pot Reaction

Synthesis ◽  
2021 ◽  
Author(s):  
Gerhard Hilt ◽  
Ludmila Hermann ◽  
Jan Fährmann
Keyword(s):  
Reaction Path ◽  
Organometallic Compounds ◽  
Alder Reaction ◽  
Diels Alder ◽  
Chiral Auxiliary ◽  
One Pot ◽  
Weinreb Amide ◽  
Diels Alder Reaction ◽  
The Stability

1,2-Oxazines were synthesised via a copper-catalysed aerobic acyl nitroso Diels-Alder reaction from 1,4-disubstituted 1,3-dienes and N-Boc-hydroxylamine. From this, 1,2-oxazinanes were received in a novel follow-up reaction path. The stability of several 1,2-oxazines and 1,2-oxazinanes towards organometallic compounds was tested to rate their operability as cyclic chiral Weinreb amide auxiliaries. 3,6-Di-tert-butyl-1,2-oxazinane gave the best results and was introduced as chiral Weinreb amide-type auxiliary to yield chiral α-substituted ketones in a diastereomeric ratio of up to 98:2. The removal of the auxiliary can be performed with BuLi to form unsymmetrical α-chiral ketones. Thereafter, the chiral auxiliary can be re-isolated and purified by sublimation in vacuum.

Aza-Diels-Alder Reaction Between 1,2-Diaza-1,3-dienes and β-Aryl-α,β-unsaturated Carbonyl Compounds. Easy One-pot Entry to 2’-Oxo-imidazo[1’,5’- f]tetrahydropyridazine

2014 ◽  
Vol 10 (6) ◽  
pp. 951-960
Author(s):  
Orazio Attanasi ◽  
Luca Bianchi ◽  
Maurizio D’Auria ◽  
Gianfranco Favi ◽  
Fabio Mantellini ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Diels Alder Reaction

Synthese neuer Pyridin-C-nukleoside der 2 ,3 -Didesoxyribose durch „inverse“ [4+2]-Cycloaddition Synthesis of Novel Pyridine-C-nucleosides of 2,3-Dideoxyribose by „Inverse“ [4+2]-Cycloaddition

1997 ◽  
Vol 52 (7) ◽  
pp. 851-858 ◽  
Author(s):  
Gunther Seitz ◽  
Johanna Siegl
Keyword(s):  
Cycloaddition Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
The Novel ◽  
Protecting Group ◽  
Enol Ethers ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Cyclic Ketene Acetals

The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine „aglycon“ of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an „inverse“ [4+2]-cycloaddition reaction. The Diels-Alder adducts spontaneously eliminate N2 and after follow-up reactions the O-TBDPS protected pyridine-C-nucleosides 13, 15, 17,19, 21 and 23 are formed. Removal of the protecting group by treatment with CF3CO2H /H2O leads to the corresponding 2’,3’-dideoxy-β-D-ribofuranosyl- pyridines.

scholarly journals One-Pot and Metal-Free Synthesis of 3-Arylated 4-Nitrophenols via Polyfunctionalized Cyclohexanones from β-Nitrostyrenes

2020 ◽  
Author(s):  
Haruyasu Asahara ◽  
Minami Hiraishi ◽  
Nagatoshi Nishiwaki
Keyword(s):  
Dimethyl Sulfoxide ◽  
Catalytic Amount ◽  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Metal Free ◽  
Diels Alder Reaction ◽  
Thienyl Group ◽  
Danishefsky's Diene

β-Nitrostyrenes underwent the Diels-Alder reaction with Danishefsky’s diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated 5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated 4-nitrophenols. The reaction of nitrostyrenes with Danishefsky’s diene could be conducted in one-pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group such as a thienyl group could be introduced into the nitrophenol framework.

scholarly journals Bicyclic allyltin derivatives through selective “one pot” hydrostannation - Diels-Alder reaction

ARKIVOC ◽  
2011 ◽  
Vol 2011 (7) ◽  
pp. 195-209 ◽  
Author(s):  
Romina A. Ocampo ◽  
Sandra D. Mandolesi ◽  
Liliana C. Koll
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Diels Alder Reaction
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