Cobalt(II) tetraphenylporphyrin-catalyzed isomerization of electronegative substituted quadricyclanes
作者:Sadao Miki、Toshinobu Ohno、Hideaki Iwasaki、Zen-ichi Yoshida
DOI:10.1016/s0040-4039(00)98671-4
日期:1985.1
Co(II)TPP1 - catalysed isomerization of a series of electronegative substituted quadricyclanes(1) to the correspondingnorbornadiene(2) was found to proceed via radicophilic attack of the metal to 1.
3-Phenylcarbamoyl-2,5-norbornadiene-2-carboxylic acid (1b) undergoes a facile and quantitative isomerization into the corresponding quadricyclane derivative (2b) under sunlight. The back isomerization of 2b to 1b proceeds quantitatively by the use of catalytic amounts of Rh2(CO)4Cl2.
Dimethyl oxaquadricyclane-2,3-dicarboxylate (1) with cyclooctyne (CO) gave, via carbonyl ylide (3a), a mixture of the exo and endo 1:1 adducts (2a, 2b) along with the novel 1:2 adduct (2c), whereas the carbocyclic analogs underwent [sigma 2s + sigma 2s + pi 2s]cycloaddition. The first examples of inverse electron demand homo-Diels-Alder reactions of oxa-, aza- and carbo-norbornadienes with CO were also described.