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A Combined Density Functional and ab initio Quantum Chemical Study of the Brandi Reaction

✍ Scribed by Estael Ochoa; Matthias Mann; Dirk Sperling; Jürgen Fabian

Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
393 KB
Volume
2001
Category
Article
ISSN
1434-193X

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✦ Synopsis

The Brandi reaction is the transformation of spiro[cyclopropane-1,5Ј-isoxazolidines] into tetrahydropyridones under thermal conditions. According to calculations performed by the restricted and unrestricted density functional theory and post-Hartree-Fock single-and multireference methods of ab initio quantum chemistry, the reaction proceeds through two biradical intermediates. These intermediates result from the homolytic cleavage of the N-O bond of the isoxazolidine ring in the first step, and the homolytic cleavage of one of the C-C bonds of the spiro-fused cyclopropane in the second. The activation energy of the rate-determining first step of the parent reaction amounts to about 40 kcal mol -1 at the RDFT/ UDFT level of theory. This energy is not much higher than [a]

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