The difference between thermal, AlCl3- and CF3 COOH-catalyzed reaction of (E)-4-benzal-1-phenyl-5-pyrazolone and 2,3-dimethylbutadiene is discussed in terms of Diels-Alderheterodiene reactivity.
Inorganic perchlorates and pericyclic reactions. IV. 1 Rate enhancement by specific cation-substrate interaction or by increased internal pressure?
作者:Giuseppe Faita、PierPaolo Righetti
DOI:10.1016/0040-4020(95)00507-5
日期:1995.8
The kinetic behaviour of Diels-Alder and ene reactions was investigated in several inorganic perchlorate-organic solvent solutions. The observed rate accelerations are the result either of specific solute-cation interactions or of the increasedinternalpressure of the media, depending on substrates, solvents, and metal cations.
Lithium perchlorate catalysis of the hetero Diels-Alder reaction: a specific lithium cation effect.
作者:G. Desimoni、G. Faita、P.P. Righetti、G. Tacconi
DOI:10.1016/s0040-4020(01)96181-2
日期:1991.9
The lithium perchlorate catalysis of the hetero Diels-Alder reaction between 1-phenyl-4-benzylidene-5-pyrazolone and ethyl vinyl ether was kinetically investigated in five solvents.
The thermal reaction between (E) or (Z)-pyrazolones (1) and 2,3-dimethylbutadiene (2) gave 1,2-dimethyl-5-arylcyclohexen-4-spiro-4' (1'-phenyl-3'-substituted-5'-pyrazolones) (3, 4), from a Diels-Alder reaction, and 4-aryl-2-isopropenyl-2-methyl-5-substituted-7-phenyldihydropyran [3,2-d] pyrazoles (5, 6), from a heterodiene reaction. The effect of the configuration of the starting pyrazolone, as well