Cyclizations of aryl enynes containing propargyl alcohol and diallylamine groups to yield indolecarbaldehydes induced by ruthenium complexes
Journal
European Journal of Inorganic Chemistry
Journal Volume
2014
Journal Issue
31
Pages
5406-5414
Date Issued
2014
Author(s)
Abstract
Abstract The reactions of RuCl(PPh 3 ) 2 Cp ([Ru]Cl, Cp = cyclopentadienyl) with aryl enynes 1a – 1c containing propargyl alcohol and diallylamine groups on the aryl ring give the carbene complexes 2a – 2c , each of which contains an indole group. With an additional methylene group, the aryl enyne 1d reacts with [Ru]Cl to afford the dihydroisoquinoline complex 3d . For 1a – 1d , the C–N bond‐forming process occurs when the triple bond is π‐coordinated to the metal center. The reaction of [Ru]Cl with the aryl enyne 1e containing an isoxazole group affords the carbene complex 2e by a C–C bond formation between the isoxazole group and C‐β of the triple bond, accompanied by the opening of the isoxazole ring. The reactions of 2a – 2c and 2e with O 2 /NEt 3 are assisted by visible light to afford the corresponding aldehydes 4a – 4c and 5e . From DFT calculations, visible light results in the partial population of the lowest unoccupied molecular orbital (LUMO), which has Ru=C antibonding character; therefore, the bond is weakened, and the oxygenation/demetallation reactions are slightly promoted.
SDGs
Type
journal article