Reactions of HDDA-Derived Benzynes with Perylenes: Rapid Construction of Polycyclic Aromatic Compounds

Abstract

Benzynes produced by the thermal cycloisomerization of tetrayne substrates [i.e., by the hexadehydro-Diels-Alder (HDDA) reaction] react with perylenes to produce novel naphthoperylene derivatives. Cyclic voltammetry and absorption and emission properties of these compounds are described. DFT studies shed additional light on the dearomatization that accompanies the reaction as well as some of the spectroscopic behavior.

Figure 1

¹H-NMR spectrum of 10a (500 MHz, CDCl₃).

Figure 2

Double adducts from benzyne addition to 10f.

Figure 3

Computed free energy changes for the reaction of benzyne (2) with perylene (1) to give the naphthoperylene 4 via extrusion of dihydrogen from the primary Diels–Alder adduct 3.

Figure 4

Cyclic voltammograms for 10c (blue) and 10g (orange).

Figure 5

Absorption (unnormalized) and fluorescence (normalized) spectra for (a) 10c (blue) and the tetraester-substituted perylene 10g (orange) and (b) 10a (green) and the electron deficient perylene 10f (red). (c) Computed (DFT) HOMO and LUMO for 10a and 10f showing the orbital density on the phenyl substituents for the LUMO of 10a and the HOMO of 10f.

Scheme 1

(a) Synthetic strategies based on perylene for the synthesis of some polycyclic aromatic compounds (PAC). (b) Possible routes to PACs through HDDA cascade reactions.

Scheme 2

Synthesis of polycyclic aromatic compounds 10a-g through reactions of tetraynes 8a-e with perylene 1 ^aIn the reactions leading to 10f and 10g, (1.2 equiv) of tetraethyl 3,4,9,10-perylene tetracarboxylate was used in place of perylene (1).