Catalysis Within the Self-Assembled Resorcin[4]arene Hexamer

Abstract

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Kinetic and Thermodynamic Modulation of Dynamic Imine Libraries Driven by the Hexameric Resorcinarene Capsule

“…Among the self-assembled architectures, the hexameric resorcinarene capsule CR 6 ( Figure 2 ) has become increasingly important in catalysis. 15 The formation of a hexameric resorcin[4]arene capsule CR 6 ( Figure 2 ) in the solid state was originally reported by Atwood, 16 whereas evidence for its formation in water-saturated chloroform or wet benzene solution was provided by Cohen 17 and co-workers by diffusion NMR experiments. The capsule is obtained by self-assembly of six resorcinarene 1 and eight water molecules, sealed by 60 H-bonding interactions.…”

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

“…After our seminal work on the use of 1 6 as a nanoreactor to bind an Au(I) catalyst and to impart unique product [ 28 ] as well as substrate [ 29 ] selectivity, the capsule attracted the attention of several other research groups bringing this self-assembled nanocontainer to the forefront in the field of supramolecular catalysts. The specific field of research has been recently reviewed [ 19 , 30 – 33 ] to underline the potentialities of this simple and efficient organocatalyst. Recent promoted reactions by the resorcin[4]arene capsule include the intramolecular ether cyclization [ 34 ], the synthesis of bis(heteroaryl)methanes [ 35 ], the imine formation [ 36 ], the Michael addition reactions of N -methylpyrrole on methyl vinyl ketone [ 37 ], the synthesis of sesquiterpene natural product derivatives [ 38 – 39 ] and the carbonyl olefin metathesis leading to 2,5-dihydropyrroles [ 40 ].…”

The Hexameric Resorcinarene Capsule as a Brønsted Acid Catalyst for the Synthesis of Bis(heteroaryl)methanes in a Nanoconfined Space

“…Supramolecular organocatalysis is an emerging area in supramolecular chemistry whose principal aim is the design of novel systems able to perform catalytic functions mimicking the chemo-, regio-, and stereoselectivity of the natural enzymes (Conn and Rebek, 1997). At this regard, much attention has been focused on designing self-assembled molecular capsules (MCs) able to catalyze organic reaction by confinement of the reactants in their internal cavity (Borsato and Scarso, 2016; Catti et al, 2016; Gaeta et al, 2019). MCs are self-assembled structures sealed by weak non-covalent interactions between the single complementary units.…”

“…Several reports clearly show that the mild Brønsted acidity of C and its ability to stabilize cationic transition states, are crucial factors for the catalytic activity of the capsule (Borsato and Scarso, 2016; Catti et al, 2016; Gaeta et al, 2019). Thus, amazing results have been reported in the last decade regarding the catalysis of chemical reactions into the nanoconfined space of the self-assembled capsule C , including the cyclization of terpenes (Zhang and Tiefenbacher, 2015, 2019; Zhang et al, 2017, 2018, 2019; Pahima et al, 2019), the hydration of the alkynes (La Sorella et al, 2016a), the carbonyl-olefin metathesis (Catti and Tiefenbacher, 2018), the sulfoxidation of thioethers (La Sorella et al, 2016b), the synthesis of substituted 1-H-tetrazoles (Giust et al, 2015), the activation of C-F bonds (Köster et al, 2019), and the iminium catalysis (Bräuer et al, 2017; La Manna et al, 2018a).…”