AgOTf‐Catalyzed Tandem Reaction of Oxabenzonorbornadienes with Arylacetylenes

Abstract

A tandem isomerization/hydroarylation reaction of oxabenzonorbornadienes and arylacetylenes was realized by using AgOTf as catalyst. 1,1‐Diarylethylenes could be easily generated as products in moderate to good yields in this tandem reaction.

Halogen‐free flame retarded rigid polyurethane foam: The influence of titanium dioxide modified expandable graphite and ammonium polyphosphate on flame retardancy and thermal stability

“…In Fig. c, the band around 580 cm −1 is characteristic vibration absorption of Ti‐O‐P, which origins from the formation of metallic phosphate . While, the band round 1252 cm −1 is the characteristic vibration absorption of P‐O‐C, which is caused by the formation of a phosphor‐carbonaceous polyaromatic structure generated from the reaction between APP and the matrix .…”

“…Although the TiO 2 /APP mixture indicates a higher T 5 than the single APP due to the addition of TiO 2 , all its T max and R max are smaller than that of APP. The results indicate TiO 2 presents catalysis in APP decomposition reaction , and the produced titanium phosphate shows high thermal stability and can further improve cohesiveness and compactness of the burning layer, which finally makes TiO 2 /APP show an improved thermal stability and residue yield. The R exp of 48.74% is obviously greater than the R the of 35.11%.…”

“…In the pattern of 80RPUF/20EG T , there is not only the characteristic diffraction peak of RPUF residue, and the peak of TiO 2 at 36.1° with a crystal space of 2.47 Å is also observed. At the same time, the anatase TiO 2 in EG T transfers to rutile TiO 2 in the combustion residue , which has been testified being beneficial for improving residue thermal stability and oxidation resistance.…”

“…Titanium dioxide (TiO 2 ) is a good FR due to its prolonging ignition time and slowing combustion speed , and it is usually considered to be a filling additive during the burning progress. In addition, as one of transition metal oxides, TiO 2 also has obvious impact on the thermal decomposition process of APP . It can accelerate the release of NH 3 and H 2 O in the earlier period during decomposition, and increase the high temperature residue in the later period due to the formation of metallic phosphate.…”

Versatile Catalytic Reactions of Norbornadiene Derivatives with Alkynes

“…Another unique and interesting feature of this reaction is that even the isolated C=C bonds, as in norbornene, can participate in this reaction and it does not involve an oxidation–reduction cycle for transition metals. In 2015, we have realized an AgOTf‐catalyzed isomerization/hydroarylation reaction of oxabenzonorbornadiene with arylacetylenes . This method provides an efficient method for the synthesis of 1,1‐diarylethylenes 25 in moderate to good yields [Eq.…”