Benzaldehyde → Perylenecarboxaldehyde

Participants

Reaction Steps

The first route employs bromoperylene PMI-12 and 3,5-diethynylbenzaldehyde (16) as the starting materials. The reaction under copper-free conditions, similar to those employed for the Sonogashira coupling of two porphyrins (Wagner, R. W. et al., Chem. Mater. 1999, 11, 2974-2983) afforded only a small amount (8.9%) of perylene-aldehyde 18 (entry 1, Table 1). The same reaction in the presence of CuI failed to produce perylene-aldehyde 18 (entry 2). We next examined the reaction with the reverse ethyne/bromo substitution pattern on the perylene and benzaldehyde. The reaction of ethynylperylene PMI-12′ and 3,5-dibromobenzaldehyde (14) (2:1 ratio) with CuI cocatalysis afforded 18 in 31% yield (entry 3). A further increase in the amount of perylene PMI-12′ (2.4:1 ratio) gave 18 in 66% yield (entry 4). Repetition of this reaction furnished 18 in 83% yield. While of limited scope, the survey of the Sonogashira reaction of perylene PMI-12 or PMI-12′ with aldehyde 14 or 16 revealed important reactivity differences between a bromoperylene and an ethynylperylene. Unlike perylene-aldehyde 15, compound 18 proved to be very soluble, thereby enabling subsequent porphyrin-forming reactions.

Provenance & Evidence