Abstract
Computational studies have been performed on potassium alkoxide-allenes, as well as potassium and lithium amido-allenes to probe the mechanism of their cyclizations to dihydrofurans and to 2,5-dihydropyrroles. A long-standing proposal envisaged electron transfer from dimsyl anions (formed by deprotonation of the solvent DMSO) but this pathway shows an exceptionally high kinetic barrier, while direct 5-endo-trig cyclization of the alkoxides and amides is much more easily achievable. The energy profiles for 4-exo-trig cyclizations onto the allenes are also explored, and the preferred formation of the observed five-membered products is rationalized.
Original language | English |
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Pages (from-to) | 6867-6871 |
Number of pages | 5 |
Journal | European Journal of Organic Chemistry |
Volume | 2017 |
Issue number | 46 |
Early online date | 11 Oct 2017 |
DOIs | |
Publication status | Published - 15 Dec 2017 |
Keywords
- alkoxyallenes
- cyclization
- density functional calculations
- furans
- heterocycles
- pyrroles