Fast and Scalable Route to Aryl Polyallyl Dendrons and Dendrimers

Abstract

In the quest for general and efficient synthetic procedures for dendrons and dendrimers, allylphenol, allylnaphthol and 6-bromonaphthalene AB 3 dendrons have been successfully prepared on a large-scale by a rapid and clean route starting from commercially available esters and allyl bromide. In contrast to the known organoiron strategy, the above-mentioned methodology enables the largescale synthesis of AB 3 dendrons in only two days.

1,1′‐Binaphthyl‐2‐methylpyridinium‐Based Peroxophosphotungstate Salts: Synthesis, Characterization, and Their Use as Oxidation Catalysts

“…This strategy, recently reported by our group, enables a large-scale preparation of aryl polyallyl dendrons and dendrimers. [19] The reaction of 1 with allylmagnesium bromide led to tetraallyl pyridinedicarbinol compound 2 in 75 % yield. The reaction of 2 with allyltrimethylsilane in the presence of Et 2 O·BF 3 led to tetraallyl dicarbinol boron adduct 3.…”

“…In addition, the 1 H NMR spectrum of boron adduct 3 shows a marked downfield shift of the two aromatic signals, probably due to the coordination of dendritic pyridine 2 (Lewis base) to boron trifluoride (Lewis acid). Further data in support of the formation of 3 were obtained by 11 B NMR (broad quadruplet at δ = 0.21 ppm) and 19 F NMR (broad multiplet at -151.6 ppm) spectroscopy. Attempts to prepare n-propyl compound 2a by catalytic hydrogenation of the allyl groups of 2 by using a Pd/C catalyst failed.…”

Dendritic Zirconium‐Peroxotungstosilicate Hybrids: Synthesis, Characterization, and Use as Recoverable and Reusable Sulfide Oxidation Catalysts

“…Dendritic quaternary ammonium salts 7a,b and their nondendritic counterpart 7c were prepared by the reaction of alcohol 3 with AB 3 phenol dendrons 4a, [8] 4b and 4-tertbutylphenol (4c), respectively (Scheme 1). The reaction of 1-chloro-4-iodobutane (in excess) with 4-hydroxybenzyl alcohol (1) led to alcohol 2 in 90 % yield.…”

Tailored Nanoparticles for Clean Technology–Achieving Size and Shape Control

“…The simple chemical methods, such as deposition-precipitation (DP) [65], ion exchange, and impregnation [66], aim to control the growth of nanoparticles on various supports via reduction/decomposition of simple precursors such as metal salts or organometallic compounds [67]. Improved control can be achieved via the immobilization of premade metal ion-containing templates (such as dendrimers [68]) onto supports, followed by careful reduction/decomposition to form well-defined nanoparticles [69][70][71][72][73][74][75][76][77]. Interestingly, dendrimers could be used both to deliver precise metal nanoparticles onto supports in fabrication of the heterogeneous catalysts, yet could also act as unsupported, homogeneous catalysts [71].…”