Synthesis 2019; 51(02): 441-449
DOI: 10.1055/s-0037-1610631
paper
© Georg Thieme Verlag Stuttgart · New York

Novel and Convenient Synthesis of 2,7-Dialkyl-1,8-dihydro-as-indacenes­

Rodrigo Faúndez
a   Departamento de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
,
Francisco Castillo
a   Departamento de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
,
Marcelo Preite
b   Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
,
Eduardo Schott
a   Departamento de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
,
Ximena Zarate
c   Instituto de Ciencias Químicas Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Av. Pedro de Valdivia 425, Santiago, Chile
,
Juan Manuel Manriquez
a   Departamento de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
,
Elies Molins
d   Instituto de Ciencia de los Materiales de Barcelona (ICMAB-CSIC), Campus UAB 08193, Bellaterra, Catalunya, Spain
,
Cesar Morales-Verdejo*
e   Centro de Nanotecnología Aplicada (CNAP), Facultad de Ciencias, Universidad Mayor, 5750 Camino la Pirámide, Huechuraba, Santiago, Chile   Email: cesar.morales@umayor.cl   Email: ichavez@uc.cl
,
Ivonne Chávez*
a   Departamento de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, Santiago, Chile
› Author Affiliations
The authors thank the financial support from the following grants: FONDECYT Grants 1161297 and 1141138.
Further Information

Publication History

Received: 30 April 2018

Accepted after revision: 08 August 2018

Publication Date:
11 September 2018 (online)


Abstract

A novel and convenient synthetic route towards dialkyl as-indacenes was achieved by alkylation of malonic esters with o-xylylene dibromide, to give the corresponding tetraester, and related diacid. The alkyl groups on the central benzene ring induce intramolecular, regiospecific cycloeliminations leading selectively to the diketones, the precursors of the corresponding 1,8-dihydro-as-indacenes. The structure of the 2,7-dimethyl-1,8-dihydro-as-indacene was determined by X-ray diffraction. The compound 2,7-diethyl-1,8-dihydro-as-indacene was characterized by means of 1H NMR, 13C NMR, FT-IR, UV/Vis measurements, electrochemistry, and elemental analysis. On the other hand, quantum chemical computations based on DFT methods were carried out to get insight into the molecular and electronic structures of the studied ligands. TDDFT approach was employed to calculate the vertical excitations and characterize the nature the UV/Vis absorption bands present in the experiments showing a very good agreement between experimental and calculated values. Finally, the reactivity of the compounds was assessed using the chemical potential (μ), chemical hardness (η), and electrophilicity (ω). Also, the electron-donating (ω), electron-accepting (ω+), and the net electrophilicity powers (ω±) indexes were studied.

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