Spiroheterocycles via Regioselective Cycloaddition Reactions of Nitrile Oxides with 5-Methylene-1H-pyrrol-2(5H)-ones

2010 ◽  
Vol 63 (3) ◽  
pp. 445 ◽  
Author(s):  
Nicola J. Beattie ◽  
Craig L. Francis ◽  
Andris J. Liepa ◽  
G. Paul Savage
Keyword(s):  
Cycloaddition Reaction ◽  
Biphasic System ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Nitrile Oxides ◽  
Facial Selectivity

Substituted 5-methylene-1H-pyrrol-2(5H)-ones underwent a 1,3-dipolar cycloaddition reaction with nitrile oxides to give the corresponding spiro heterocycles. Critical to this reaction was the development of a biphasic system for base-induced dehydrohalogenation of hydroximoyl chlorides, to give nitrile oxides, in the presence of a base-sensitive dipolarophile. A substituted N-tolyl 5-methylene-1H-pyrrol-2(5H)-one exhibited atropisomerism, which in turn led to a 4:1 facial selectivity during cycloaddition.

Enolate-mediated 1,3-dipolar cycloaddition reaction of β-functionalized ketones with nitrile oxides: direct access to 3,4,5-trisubstituted isoxazoles

2016 ◽  
Vol 14 (23) ◽  
pp. 5246-5250 ◽  
Author(s):  
Xiao Zhou ◽  
Xianhong Xu ◽  
Zhenyan Shi ◽  
Kun Liu ◽  
Hua Gao ◽  
...  
Keyword(s):  
Cycloaddition Reaction ◽  
Direct Access ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Nitrile Oxides ◽  
High Yields

Enolate-mediated [3 + 2] organocatalytic 1,3-dipolar cycloaddition reactions of β-functionalized ketones with nitrile oxides have been developed. This strategy could generate 3,4,5-trisubstituted isoxazole in high yields and regioselectivities.

Regio- and diastereo-selective formation of Isoxazoline Derivatives by Lewis acid Mediated 1,3-dipolar Cycloaddition Reactions of Nitrile Oxide

2007 ◽  
Vol 2007 (7) ◽  
pp. 394-396 ◽  
Author(s):  
Saori Hayashi ◽  
Akira Mori ◽  
Masatoshi Nishina ◽  
Masanori Sumimoto ◽  
Kenzi Hori ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Cycloaddition Reaction ◽  
Chiral Auxiliary ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Magnesium Perchlorate ◽  
Nitrile Oxides ◽  
Selective Formation

In the presence of magnesium perchlorate, 1,3-dipolar cycloaddition reactions of nitrile oxides to crotonamide bearing 4-benzyl-5,5-dimethyl-1,3-oxazolidin-2-one as the chiral auxiliary proceeded with a regio- and diastereo-selective manner to afford the corresponding chiral 2-isoxazoline. The mechanisms underlying the diastereoface selection in the cycloaddition reaction were investigated using the B3LYP/6-31G* level of theory.

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

1,3-Dipolar cycloaddition reactions of nitrile oxides in the synthesis of natural compounds and their analogues

2001 ◽  
Vol 70 (8) ◽  
pp. 641-653 ◽  
Author(s):  
Anna I Kotyatkina ◽  
Vladimir N Zhabinsky ◽  
Vladimir A Khripach
Keyword(s):  
Natural Compounds ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Nitrile Oxides
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