Palladium-Catalyzed Heteroannulation of Indole-1-carboxamides with [60]Fullerene and Subsequent Electrochemical Transformations

Abstract

A highly efficient heteroannulation between [60]­fullerene (C60) and N-methoxy-1H-indole-1-carboxamides has been successfully achieved via the palladium-catalyzed C–H activation and subsequent cyclization. This protocol has remarkable functional group tolerance for the synthesis of C60-fused 3,4-dihydro­pyrimido­[1,6-a]­indol-1­(2H)-ones. Furthermore, the electrochemically generated dianionic C60-fused 3,4-dihydro­pyrimido­[1,6-a]­indol-1­(2H)-ones can be regioselectively transformed into 1,2,3,4-, 1,2,3,16-, and 1,4,9,25-adducts of C60.

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

“…Even though we could capture the intermediate leading to the cyclized 1,2,4,17-adduct, the instability of this unique cyclized product precluded its characterization by 13 C NMR and single-crystal X-ray analysis. Bearing the aforementioned different reactivity of the same dianionic species toward alkylating and acylating reagents and instability of the previously obtained tetrafunctionalized product in mind, our continuous efforts in electrochemical functionalization of fullerene derivatives [25,28,29,[38][39][40][41] stimulated us to investigate the reaction of the dianionic [60]fulleroindolines 1a-c 2-with phthaloyl chloride in order to contrast their reactivity behavior and to see if the unprecedented tetrafunctionalized cis-3 ′ isomers (type G) and "S"-shaped hexafunctionalized products (type H) bearing two acyl groups can be generated in the present case [42]. It turns out that these two unique types of tetra-and hexafunctionalized products can be successfully synthesized and are stable up to 107−275°C.…”

Electrochemically Promoted Benzylation of [60]Fullerooxazolidinone

“…All of these reactions involved the rearrangement of the indoline moiety from a [6,6]-bond to a [5,6]-bond. Similar electrosynthesis involving rearrangements of heterocyclic moieties on the fullerene surface for other C 60 -fused heterocycles resulted in 1,2,3,4-, 1,2,3,16-and 1,4,9,25-adducts [31][32][33][34][35]. The electrochemical reactions of heterocyclic fullerene derivatives fused with two heteroatoms have also been reported.…”

Palladium-Catalyzed Tandem Dehydrogenative [4 + 2] Annulation of Terminal Olefins with N-Sulfonyl Amides via C–H Activations

“…Palladium-catalyzed directed C­(sp 2 )–H functionalization of amides is an appealing area, especially the cascade cyclization reactions, , since the CONHR group can serve not only as a directing group for C­(sp 2 )–H functionalization but also as a precursor to the C–N bond. Hence, we hypothesized that benzamides could be chosen as the dual nucleophilic sources to perform the dehydrogenative [4 + 2] annulation with terminal olefins.…”