222631-97-2Relevant academic research and scientific papers
A route to 1,4-prop[2]enoisoquinolines via the cyclisation of triene-conjugated nitrile ylides
Strachan, Jon-Paul,Sharp, John T.,Crawshaw, Melanie J.
, p. 443 - 451 (2007/10/03)
Triene-conjugated nitrile ylides of the types 18 and 20 with α,β aromatic and γ,δ; ε,ζ olefinic unsaturation undergo intramolecular cyclisation on to the γ,δ bond via a formal 1,1-cycloaddition reaction to give respectively endo- and exo-1-alkenylcyclopropa[c]isoquinolines 23 and 25 as primary products. The endo-isomers 23 rearrange spontaneously at 0°C to give 1,4-dihydro-1,4-prop[2]enoisoquinolines 24 via an aza-Cope reaction. The exo-isomers 25 give the same product on heating at 70°C via equilibration with the endo form 26 as the primary step, provided that the concentration of the latter at equilibrium is not strongly disfavoured by the steric effect of substituents R1 and R2. If it is then an alternative rearrangement also occurs to give the azabenzo[3,4]barbaralane derivative 29.
