Ernest Cerutti

Regiochemistry of the cycloadditions of diphenylnitrilimine to coumarin, 3-ethoxycarbonyl and 3-acetyl coumarins: A reinvestigation

Abstract The cycloaddition reactions of diphenylnitrilimine to coumarin, 3-ethoxycarbonyl and 3-acetylcoumarins were studied. The observed regiochemistry of the reaction with the coumarin 4a was the same as the one suggested by other researchers. For the coumarins 4b and 4c bearing an electron withdrawing group at the 3-carbon atom, our results invalidate the previously reported regiochemistry. The presence of an electron-withdrawing group at the 3-C atom of coumarin derivatives reverses the regioselectivity of cycloaddition of diphenylnitrilimine to the dipolarophilic double-bond.

Reaction of diarylnitrilimines with 3,3-dimethyl-2-indanone enamines; the first example of a stable zwitterionic nitrilimine–enamine cycloadduct

The reaction of the title compounds leads to a zwitterionic cycloadduct as is demonstrated by 1H, 13C, and 15N n.m.r. spectroscopy

Etude spectroscopique RMN 1H d'aryl-1 méthyl-2 benzo(e)indoxyles et d'aryl-1 méthyl-2 benzo(e)indoles. Un nouvel exemple d'empêchement à la libre rotation en série dihydroindolique

Abstract The proton magnetic resonance spectra of some N -aryl 2-ethoxycarbonyl 2-methyl benzo(e)indoxyles and N -aryl 2-methyl benzo(e)indoles have been investigated. The data for one of these compounds are best rationalized on the basis of a hindered rotation about the N -aryl bond. The attribution of the signals to each conformation is obtained from the chemical shifts in the “methyl region”.