Trialkylamine-Catalyzed Aldolization of Unprotected 1,3-Dihydroxyacetone (DHA) toward C–C Bond-Linked Tetraol Surfactants

Abstract : The aldolization of unprotected 1,3-dihydroxyacetone (DHA) was studied under mild conditions (20 °C) in a mixture of water/EtOH using hydrocinnamaldehyde as a model substrate. It was shown that trimethylamine is the most effective base for this transformation, giving the corresponding aldol with up to 98% selectivity and 82% yield. The method was extended to a range of (biobased) aldehydes to give α-hydroxyketones with 29–70% isolated yields. These α-hydroxyketones were reduced under hydrogen using 5%-Ru/Al2O3 in EtOH at 100 °C to give tetraols with 79–97% isolated yields. The physicochemical properties of these tetraols were studied (CMC, Krafft point, PIT-slope method), and these studies revealed that this new class of C–C bond-linked nonionic surfactants exhibits high effectiveness, reducing the surface tension of water.