Phenyl ether-terminated products

Figure 2. Mol wt distribution of phenyl ether-terminated products, [THF] in cyclohexane — 10.2M f(CF,SO,)tO] — 0.079M. (-------) Prod-...

Preparative Photolysis. The preparative photolysis of an aqueous solution (pH=8.5) of AETSAPPE (2.5 M) was conducted in a 1-inch diameter quartz test tube in a Rayonet Reactor (Southern New England Radiation Co.) fitted with 254 nm lamps. Within two hours the solution gelled and the reaction was terminated. Upon acidification the solution cleared, and the product could be re-precipitated by addition of base. This indicates loss of the thiosulfate functionality. The product was dissolved in dilute HC1, precipitated with acetone, and filtered. This process was repeated three times, and the final precipitate was washed with water. The product (20 to 30 mg) was dried in vacuo for 24 hours and stored in a dessicator until use. Comparison of the13 C NMR spectrum of the product with the starting AETSAPPE 13C NMR spectrum clearly shows that the thiosulfate methylene peak shifted upfield, from 39 ppm to 35 ppm. The complete 13 C NMR and IR analysis of the product were consistent with the disulfide product. Further, elemental analysis of the product confirmed that the product was the desired disulfide product 2-amino (2-hydroxy 3-(phenyl ether) propyl) ethyl disulfide (AHPEPED) Expected C 58.39, H 7.08, N 6.20, S 14.18 actual C 58.26, H 7.22, N 6.06, S 14.28. 

In 1967 elimination of phenol from allyl phenyl ethers to form 1,3-diene in the presence of a palladium catalyst was reported briefly by Smutny. Later, Tsuji applied the Pd-catalyzed elimination reaction of terminal allylic compounds for the synthesis of terminal 1,3-dienes.Thus, elimination of acetic acid and phenol from allylic acetates and allyl phenyl ethers was carried out by refluxing the allylic compounds in dioxane or toluene in the presence of catalytic amounts of palladium acetate and PPha as a ligand for the palladium catalyst (Table 1). The allylic isomers were converted to the same products. No reaction takes place with allylic methyl ether, an allylic alcohol, or an allylic amine, which cannot easily form 7r-allylpalladium complexes by oxidative addition. 

Moran et al. 41 attached the Cr(CO)3 moiety to tetrakis(phenylsilane) 32 (prepared by the hydrosilylation of tetraallylsilane with four equivalents of dimethylphenylsilane) by treatment with excess Cr(CO)6 in dibutyl ether—THF at 140 °C affording the air-stable, crystalline tetrakis(chromium carbonyl) dendrimer 33, which was also prepared by reaction of tetraallylsilane with [r76-C6H5Si(Me)2H]Cr(CO)3) (Scheme 8.9). 42a Reaction of the corresponding eight phenyl-terminated analogues afforded the partially metalated silane dendrimer 34 as the major product, even with an excess of Cr(CO)6. 

Asymmetric hydrosilylation of 2-phenyl-1-butene yields enantiomeric excess ee) values as high as 68% [149]. Products obtained by sequential cyclization/ silylation reactions of 1,5-dienes and 1,6-dienes feature in the suggested mechanistic scenario (Scheme 8) [149, 155]. Furthermore, hydrosilylation of terminal olefins achieved both excellent chemoselectivity in the presence of any internal olefin, and functional-group compatibility with halides, ethers, and acetals [155]. 

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