A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

The hexameric resorcin[4]arene capsule as a self-assembled organocatalyst promotes a series of reactions like the carbonyl–ene cyclization of (S)-citronellal preferentially to isopulegol, the water elimination from 1,1-diphenylethanol, the isomerization of α-pinene and β-pinene preferentially to limonene and minor amounts of camphene. The role of the supramolecular catalyst consists in promoting the protonation of the substrates leading to the formation of cationic intermediates that are stabilized within the cavity with consequent peculiar features in terms of acceleration and product selectivity. In all cases the catalytic activity displayed by the hexameric capsule is remarkable if compared to many other strong Brønsted or Lewis acid

Triphenylene based metal-pyridine cages

C3-symmetric pyridine containing tris-benzyl-O-substituted hexahydroxytriphenylene derivatives were prepared and used in combination with square-planar Pd(II) and Pt(II) complexes for the self-assembly of molecular cages in solution. The formation of a trigonal bipyramid M3L2 cage was demonstrated by multinuclear NMR analyses and pseudo 2D DOSY experiments and supported by semi-empirical calculation

Recent metallosurfactants for sustainable catalysis in water

In the field of green chemistry, micellar catalysis plays a central role for organic solvent replacement. Micelles ensure the solubilization or dispersion of catalyst and organic substrates in water imparting unique features in terms of chemo-, regio- and stereoselectivity. For metal-catalyzed reactions, a more robust approach for catalyst recycling consists in the synthesis of socalled metallosurfactants, in which a hydrophilic metal– containing headgroup is endowed with a hydrophobic ponytail, leading in water to the formation of metallomicelles. This fastgrowing field of research is critically reviewed in this contribution, describing new trends and classifying the literature since 2017 based on the nature of the newly formed bond. Particular emphasis is reported on the specific features of metallosurfactants in terms of activities, selectivities and recyclability of the self-assembling catalysts

Minimalistic β-Sitosterol based Designer Surfactants for Efficient Cross-Coupling in Water

In this contribution, we report about the synthesis, the aggregation properties and their application in cross-coupling catalysis of two new designer surfactants comprising a rigid hydrophobic portion based on β-sitosterol directly linked by an etheric bond to methyl polyoxoethylene chains. The proposed am- phiphilic compounds represent a minimalistic approach with respect to the Lipshutz’s third generation designer surfactant Nok. The amphiphiles displayed improved chemical stability, shorter synthesis, and good properties in Pd-catalyzed cross-coupling reactions in water under mild conditions, as compared with other neutral commercially available surfactant