Incorporation of Functional Guest Molecules into an Internally Functionalizable Dendrimer through Olefin Metathesis

Abstract

A poly(aryl ether) dendrimer bearing 22 allyl groups throughout the interior of the molecule has been prepared using a convergent synthetic approach. The internal functionalities of this dendrimer can be used to attach small molecule guests to the interior of the dendrimer using olefin metathesis. A ruthenium-based Grubbs catalyst was used to covalently attach an allylated pyrene and imidazolidinone via cross-metathesis. The extent of coupling was estimated by UV, NMR, and elemental analysis data. The high tolerance of cross-metathesis to a range of functional groups enables the incorporation of a wide range of molecules and provides access to different inner environments in one step from a single source of dendrimer.

New chimeric anti-tubercular dendrimers with self-delivering property

“…They are monodisperse and usually highly symmetric, spherical compounds. The main features of dendrimers is related to functional groups on the molecular surface, though, some dendrimers possess internal functionality (Antoni et al, 2009;McElhanon and McGrath, 2000;Liang and Fréchet, 2005). Dendrimers are investigated as carrier for drug delivery system (Anil et al, 2002).…”

Chemoselectivity Improvement via Partial Shielding of an Imidazole Active Site in Branched/Dendritic Homogeneous Catalysts of the Baylis–Hillman Reaction

“…[12,13] Likewise,ahydrophobic polymeric backbone or matrixinfluences at times the outcome of the reactions promoted by supported catalysts. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The latter were recently used as nanoreactors for organocatalytic transformationsi na queous media, which otherwise require apolar organic solvents.I ns uch cases,l ocalization of the catalytic units in the hydrophobicc ore,c ombined with the sequestration of the organic reactants by the core ("concentration effect") and the exclusion of the hydrophilic products, if any, from the nanoreactor,f requently lead to as ubstantial increase in the reactiony ield. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The latter were recently used as nanoreactors for organocatalytic transformationsi na queous media, which otherwise require apolar organic solvents.I ns uch cases,l ocalization of the catalytic units in the hydrophobicc ore,c ombined with the sequestration of the organic reactants by the core ("concentration effect") and the exclusion of the hydrophilic products, if any, from the nanoreactor,f requently lead to as ubstantial increase in the reactiony ield.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The latter were recently used as nanoreactors for organocatalytic transformationsi na queous media, which otherwise require apolar organic solvents.I ns uch cases,l ocalization of the catalytic units in the hydrophobicc ore,c ombined with the sequestration of the organic reactants by the core ("concentration effect") and the exclusion of the hydrophilic products, if any, from the nanoreactor,f requently lead to as ubstantial increase in the reactiony ield. [16][17][18][19][20][21][22][23][24][25]32] These internally functionalized dendritic catalysts demonstrated, in anumber of cases,enhanced reactivity,a sw ella ss ubstrate selectivity/specificity.W eh y-pothesized that similar core-shell architecturesc ould also address the chemoselectivity parameter in certain reactions. [14,31] An umber of groups,w orking with dendrimers, demonstrated that the immobilization of functional units,i np articularc atalytic centers,i no rn eart he dendrimerc ore,c ombined with the encapsulation of the core region by the outer shell, can imparts pecial properties on the functioningo ft hese units.…”

Immobilization of MacMillan Imidazolidinone as Mac‐SILC and its Catalytic Performance on Sustainable Enantioselective Diels–Alder Cycloaddition

“…To address these issues, the MacMillan catalyst was covalently immobilized on JandaJel,8 PEG,9 polymer capsules,10 liquid crystals,11 fluorous solvent12 or silica 13. Alternatively, non‐covalent immobilization was carried out by incorporation into dendrimers,14 entrapment in montmorillonite15 or ionic bonding on polymers,16 although successful recycle use has yet to be explored in both covalent and non‐covalent immobilizations.…”