Easy entry to donor/acceptor butadiene dyes through a MW-assisted InCl3-catalyzed coupling of propargylic alcohols with indan-1,3-dione in water

• A novel indium-catalyzed C–C coupling reaction is presented.
• It allowed the preparation of new butadiene dyes from alkynols and indan-1,3-dione.
• The process takes place in pure water under MW irradiation.
• This is the first example of a Meyer–Schuster/Knoevenagel tandem process in water.

In this contribution, the high-yield preparation and optical properties of some donor-acceptor butadiene dyes, generated by coupling of different 1,1-diaryl-2-propyn-1-ols with indan-1,3-dione, are presented. The reactions, which involve the initial Meyer–Schuster rearrangement of the aromatic alkynols and subsequent condensation of the resulting enals with the β-dicarbonyl compound, proceeded cleanly in water, under MW irradiation, in the presence of catalytic amounts of the inexpensive Lewis acid InCl3. A single-crystal X-ray diffraction study of one of these dyes is also included.

The preparation of novel push-pull butadiene dyes in water, by catalytic coupling of terminal propargylic alcohols with indan-1,3-dione, is described. Inexpensive InCl3 was used as the catalyst and microwave irradiation as the heating source.Figure optionsDownload as PowerPoint slide