REACTIVITY, STEREO- AND REGIOSELECTIVITY OF DIELS-ALDER REACTIONS BETWEEN FIVE-MEMBERED HETEROCYCLES AND DANISHEFSKY'S DIENE

Walter Fabian, Romina Brasca, Maria Kneeteman, Pedro Mancini
2013 Proceedings of The 17th International Electronic Conference on Synthetic Organic Chemistry   unpublished
Conceptual density functional theory (chemical hardness η, electronic chemical potential µ, global and local electrophilicity index ω and ω k , Fukui function f + k ) is used to predict reactivity, stereo-and regioselectivity of the Diels-Alder (DA) reaction between 2-nitropyrrole and its 1tosylated derivative with Danishefsky's diene to yield 5-hydroxyindoles. A detailed mechanistic study of various possible reaction channels is done by DFT [B3LYP/6-31G(d)] calculations. Solvent effects
more » ... e) are taken into account by the CPCM bulk solvation model. In principle, the nitropyrrole can either act as diene involving the nitro group (hetero Diels-Alder reaction, HAD) or alternatively as alkene in a "normal" Diels-Alder reaction. The experimentally observed product 5-hydroxy-1-tosylindole can be formed either directly by Diels-Alder reaction of the nitropyrrole acting as alkene or by rearrangement of the dihydrooxazine N-oxides. The primary cycloadduct with the nitropyrrole acting as alkene is found to be unstable reacting further by extrusion of nitrous acid to 5-hydroxyindole. Finally, the results are compared with those obtained for the analogous furans, thiophenes, and selenophenes.
doi:10.3390/ecsoc-17-e002 fatcat:xo2sbzqolvc5rjauuhpzt6txei