TY - JOUR
T1 - 1,3-Dipolar cycloaddition of nitrile imines with α,β-unsaturated lactones, thiolactones and lactams
T2 - Synthesis of ring-fused pyrazoles
AU - Chandanshive, Jay Zumbar
AU - González, Pedro Blas
AU - Tiznado, William
AU - Bonini, Bianca Flavia
AU - Caballero, Julio
AU - Femoni, Cristina
AU - Comes Franchini, Mauro
N1 - Funding Information:
We acknowledge financial support from University of Bologna . W.T. acknowledge Fondecyt (Grant No. 11090431 ).
PY - 2012/4/22
Y1 - 2012/4/22
N2 - 1,3-Dipolar cycloaddition of nitrile imines with α,β-unsaturated five- and six-membered lactones, thiolactones and lactams gave ring-fused pyrazoles. Regioisomeric mixtures have been obtained with the 5-substituted pyrazole as the major cycloadduct. Only with the five-membered lactone the major product was the 4-acyl derivative. Computational studies, the use of the topological analysis of the Fukui functions and the potential energy surfaces (PES) theory allowed a theoretical description of the local reactivity in agreement with the observed high regiochemistry and with the role of the heteroatom adjacent to the carbonyl group.
AB - 1,3-Dipolar cycloaddition of nitrile imines with α,β-unsaturated five- and six-membered lactones, thiolactones and lactams gave ring-fused pyrazoles. Regioisomeric mixtures have been obtained with the 5-substituted pyrazole as the major cycloadduct. Only with the five-membered lactone the major product was the 4-acyl derivative. Computational studies, the use of the topological analysis of the Fukui functions and the potential energy surfaces (PES) theory allowed a theoretical description of the local reactivity in agreement with the observed high regiochemistry and with the role of the heteroatom adjacent to the carbonyl group.
KW - Dipolar cycloadditions
KW - Lactams
KW - Nitrile imines
KW - Pyrazoles
KW - Thiolactones
KW - α,β-Unsaturated lactones
UR - http://www.scopus.com/inward/record.url?scp=84859159296&partnerID=8YFLogxK
U2 - 10.1016/j.tet.2012.02.068
DO - 10.1016/j.tet.2012.02.068
M3 - Article
AN - SCOPUS:84859159296
VL - 68
SP - 3319
EP - 3328
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 16
ER -