Work

Synthesis of Fused Cyclic Aryl Amino Carbon Carbene Salt Precursors ([f-CArACH]+) Incorporating an Auxiliary Arene and Isolation of a Cu(I) Complex

Year: 2025

Type: article

Abstract: The synthesis of a small library of fused Cyclic Aryl Amino Carbon (f-CArAC) carbene precursors in the form of 1,1,2,4-tetraaryl-1H-isoindol-2-ium triflate (6), (7-R) (R = tBu, CF3) or 3,3-dimethyl-2,8-bis-arene-substituted-3,4-dihydro-isoquinolin-2-ium hydrogen-dichloride (8) and 2,4,8-tri(substituted)-isoquinolin-2-ium tosylate salts (12) has been achieved. All of them feature an arene incorporated on the annulated benzene ring of the corresponding heterocycle, introduced at the early stages of their synthesis via the Suzuki cross-coupling reaction between 2,6-dibromo-benzaldehyde and the desired aryl boronic acid. The terphenyl-2′carbaldehyde by-products of this Suzuki reaction are useful starting points for the preparation of two new iminium iodide salts (10-R) (R = H, CF3) as potential precursors to access ACyclic Amino Carbon (ACAC) carbenes. Compounds (6) and (7-tBu) react readily with hydroxide either in THF or in a biphasic Et2O/aqueous OH− solution to produce the substituted isoindolinols (13) and (14), respectively. The thermal dehydration of the former generates the corresponding f-CArAC carbene in situ, which is trapped by Cu(I)Cl furnishing, a rare example of a two-coordinate Cu(I) complex (15) supported by this new ligand scaffold.

Source: Organics

DOI: 10.3390/org6040051

Authors: Polidoros Chrisovalantis. Ioannou, Nikolaos Tsoureas, Sevasti-Panagiota Kotsaki

Institution: National and Kapodistrian University of Athens

Language: English

Topic: N-Heterocyclic Carbenes in Organic and Inorganic Chemistry

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,207

Funders: European Commission, National and Kapodistrian University of Athens, Hellenic Foundation for Research and Innovation