Cross-Linking Dendrimers with Allyl Ether End-Groups Using the Ring-Closing Metathesis Reaction

Abstract

A third generation Frechet-type dendrimer containing 24 allyl ether end-groups was synthesized, cross-linked using the ring-closing metathesis (RCM) reaction, and the core was removed hydrolytically without significant fragmentation. The results are analogous to those previously reported for homoallyl ether dendrimers (Wendland, M. S.; Zimmerman, S. C. J. Am. Chem. Soc. 1999, 121, 1389-1390) suggesting that the less readily available homoallyl ether dendrimers can be replaced by their allyl ethers analogues in a range of applications.

Synthesis of Fréchet-type poly(aryl ether) dendrimers with allyl end groups: comparative convergent and divergent approaches

“…The spectral data of 3 was compared with that already published. 5,12 1,3,5-Tris-[3,5-bis(allyloxy)benzyloxy]benzene (6). To a round bottom flask containing K2CO3 (1.53 g, 11.1 mmol) in DMF:THF (60:12 mL) as solvent, under nitrogen atmosphere, was added phloroglucinol 5 (0.20 g, 1.23 mmol) and the mixture was heated at 70 °C followed by addition of 3,5-diallyloxybenzyl chloride 2 (0.88 g, 3.69 mmol).…”

“…Although in general the yields are good, when the reaction between the dendron of the second generation and 1,3,5-tris-(4-hydroxyphenyl)benzene (THPB) as core is carried out, the yield falls to 53%. Motivated by potential applications of poly(aryl ether) dendrimers with allyl ether end groups such as preparation of cross-linked dendrimeric materials via ring closing metathesis reactions, [2][3][4][5] the advantage of selective removal of the protecting groups with Pd catalysts to provide peripheral hydroxyl groups that can be functionalized with hydrophobic chains to form new supramolecular polymers, 6 but mainly because these groups are active for hydrosilylation reactions to obtain metallodendrimers with high-boron-content that can be applied in boron neutron capture therapy (BNCT), 7 we have continued working on the synthesis of dendrimers with allyl ether terminal groups.…”

Brief Timelapse on Dendrimer Chemistry: Advances, Limitations, and Expectations

“…Cross metathesis reaction in polyolefin molecules is often condemned by the possibility of intramolecular ring closing metathesis (RCM) or by the intermolecular cross‐linking . However, in the Astruc group we demonstrated that it is possible to use olefin cross metathesis to efficiently functionalize polyolefin dendrimers using the Grubbs catalyst 2 nd generation and acrylate derivatives (olefins bearing electron withdrawing groups) .…”

“…Cross metathesis reaction in polyolefi n molecules is often condemned by the possibility of intramolecular ring closing metathesis (RCM) or by the intermolecular cross-linking. [ 27 ] dendrimers up until generation nine, which possesses approximately 177 000 terminal groups ( vide infra , Section 3). [ 13a , 24 ] In the Astruc group, we further developed a one-pot synthetic strategy that consisted in hydrosilylation of a nonaallyl dendritic core using H(CH 3 ) 2 SiCl followed by reaction with a phenolate dendronic brick bearing three allyl groups.…”

Novel Cross‐Linked Films Prepared from Hyperbranched Poly(amine‐ester)

“…These special structure and properties are drawing more and more attentions on HBPs in the fields of catalysts, [1][2][3] organic nanoparticles, [4][5][6] ultra thin films, [7,8] etc. Concerning the synthesis efficiency, one of the reasonable exploration trends is to fabricate larger-matrix materials with novel properties using HBPs (especially for those in sticky states).…”