New Dyes Based on Extended Fulvene Motifs: Synthesis through Redox Reactions of Naphthoquinones with Donor–Acceptor Cyclopropanes and Their Spectroelectrochemical Behavior

Abstract

Novel dyes based on extended fulvene motifs are reported. The carbon skeleton was generated by ac atalyzed additiono fd onor-acceptor cyclopropanes to naphthoquinone. The hydroxy group at the central ring of the tricyclic fulvenem otif was converted into the triflate, which reacted efficientlyw ith aw ide range of nucleophiles, resulting in substitution and thereby providingn ew derivatives. The synthetic versatility allowed us to investigate the absorption, electrochemical, and UV/Vis-NIR spectroelectrochemical properties of these dyes as af unctiono ft he substituents. The dyes were shown to participate in reductivee lectrochemistry,t he reversibility of which can be improved by appropriate selection of the substituents. Additionally,f irst signs of NIR electrochromism are presented, openingn ew avenues for the futurei nvestigations of such dyes.Supporting Information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Diastereoselective Synthesis of Cycloheptannelated Indoles via Lewis-Acid-Catalyzed (4 + 3)-Cyclization of Donor–Acceptor Cyclopropanes

“…Donor–Acceptor (D–A) cyclopropanes as versatile 1,3-zwitterion precursors have increasingly been explored in organic synthesis. Recently, quite a few methodologies have been established, including rearrangements, ring-opening reactions, and ( n + 3)-cyclizations (Scheme b) . Compared with the fact that (2 + 3)- − and (3 + 3)- , cyclizations of D–A cyclopropanes have been extensively explored for the synthesis of five- and six-membered skeletons, less attention has been devoted to (4 + 3)-cyclization , for the construction of seven-membered rings, especially for the synthesis of seven-membered carbocycles.…”

A substrate-dependent reaction of 1-aryl-2-alkyl-1,2-diketones with 2-aroyl-1-chlorocyclopropanecarboxylates: selective access to 2′,5′-dicyclopropoxy-1,1′:4′,1′′-teraryls and pentafulvenes

“…Next, the prepared pentafulvene 4qa was treated with aqueous hydrazine in EtOH at 40 °C for 14 h. Excitingly, a novel class 32 of 2 H -cyclopenta[ d ]pyridazine scaffolds 13 was obtained in 88% yield as shown in Scheme 7.…”

Stereoselective Synthesis of 4,5‐Dihydroisoxazole Derivatives from 1,1‐Dicyanocyclopropanes and Hydroxylamine Hydrochloride

“…In contemporary organic synthesis, donor‐acceptor (D‐A) cyclopropanes were used widely as valuable building blocks for the construction of complex architectures [67–74] . The special intramolecular tension of D‐A cyclopropanes with diversified substituent patterns easily resulted in various opening‐ring disconnections to afford differently 1,3‐zwitterionic reactants [75–83] . 1,3‐Zwitterionic reactants can undergo various transformations such as ring‐opening reactions, rearrangements, and cycloaddition reactions with electrophilic or nucleophilic components.…”