ChemInform Abstract: Reactions of Triene-Conjugated Diazo-Compounds: Reaction Paths from o-(1,3-Dienyl)aryldiazomethanes to 3,8-Methano-1,2-diazocines and to Pyrrolo[2,1-a]phthalazines via Intramolecular [3 + 2] and 1,1-Cycloaddition Reactions.

Abstract

The reaction paths followed by the triene-conjugated diazo-compounds 7, which have α,β aromatic and γ,δ; e,ζ olefinic unsaturation, depend strongly on the nature of the substituents R1 and R2. Those with R1,R2 = (CH2)3, 7a–e, react at room temperature via an intramolecular (3 + 2) cycloaddition reaction of unprecedented regioselectivity to give the bridged benzodiazocines 18a–e in high yield. Those with R1 = Me and R2 = Ph, 7f and 7g, react at 80 °C to give the hydrocarbons 19f,g and, via new chemistry, the pyrrolo[2,1-a]phthalazines 24f,g. The structures of compounds 18a, 19a and 24f have been determined by X-ray crystallography.