Molecules 1997, 2(3), 57-61; doi:10.3390/20300057
Article

Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition

Received: 31 August 1996; Accepted: 3 December 1996 / Published: 8 April 1997
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The cycloaddition of the chiral nitrile oxide 1 to 1-R-substituted 3,3-methylene-5,5-dimethyl-2-pyrrolidinones 2 (where R is H, n-butyl-, 1,1-dimethylethoxycarbonyl-, 1-methylethenyl- and acetyl-) proceeds regioselectively under the formation of spiroisoxazolines, namely 7-R-substituted-6-oxo-8,8-dimethyl-1-oxa-2,7-diazaspiro[4,4]non-2-enes 5 and 6. The asymmetric induction expected by the a-chiral centre of the nitrile oxide 1 was not very effective, diastereoisomers 5 and 6 were formed in an approximate 50:50 ratio. The stereoselectivity of the 1,3-dipolar cycloaddition of the arylnitrile oxide 7 with the chiral lactam 3 and the achiral lactone 4 are investigated. The attack of the 1,3-dipole occurred from the less hindered face of the dipolarophile 3 and 4, giving the major isomer 8 and 10, respectively.
Keywords: Lactams; lactones; stereoselectivity of 1; 3-dipolar cycloadditions; nitrile oxides
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MDPI and ACS Style

Micuch, P.; Fisera, L.; Ondrus, V.; Ertl, P. Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition. Molecules 1997, 2, 57-61.

AMA Style

Micuch P, Fisera L, Ondrus V, Ertl P. Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition. Molecules. 1997; 2(3):57-61.

Chicago/Turabian Style

Micuch, Peter; Fisera, Lubor; Ondrus, Vladimír; Ertl, Peter. 1997. "Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition." Molecules 2, no. 3: 57-61.

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