130995-12-9Relevant articles and documents
Design of multilayered polymeric dielectric insulators for advanced microelectronics packaging
Park,Chiesel,Economy
, p. 351 - 363 (1994)
2,2-Bis[ 4-{ (4-fluorophenyl)buta-1,3-diynyl} phenyloxyphenyl] hexafluoropropane and co-polymer of 1,4-bis(4-fluorophenyl)buta-1,3-diyne and hexafluorobisphenol-A were prepared for the use as photosensitive multilayered polymeric dielectric insulators. Th
Alkyne oxidations by cis-dioxoruthenium(VI) complexes. A formal [3 + 2] cycloaddition reaction of alkynes with cis-[(Cn*)(CF3CO2)Ru(VI)O2]ClO4 (Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane)
Che,Yu,Chan,Cheng,Peng,Lau,Li
, p. 11380 - 11392 (2000)
cis-Dioxoruthenium(VI) complexes, [Cn*(CF3CO2)Ru(VI)O2]ClO4 (1) (Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane) and cis-[(Tet-Me6)Ru(VI)O2](ClO4)2 (2) (Tet-Me6 = N,N,N',N'-tetramethyl-3,6-dimethyl-3,6-diazaoctane-1,8-diamine), oxidize disubstituted alkynes to 1,2-diketones selectively in good to excellent yields under ambient conditions. The reactions proceed via the formation of dark blue [(Cn*)(CF3CO2)Ru(IV)OC2R1R2O]+ intermediates, which display a characteristic UV-visible absorption band at 550-680 nm. With bis(trimethylsilyl)acetylene as substrate and 1 as the oxidant, the intermediate was isolated and structurally characterized by X-ray crystallography as a [3 + 2] cycloadduct. The kinetics of the cycloaddition of 1 with various substituted trimethylsilylacetylenes has been studied by stopped-flow spectrophotometry. With the exception of bis(trimethylsilyl)acetylene, the second-order rate constants were found to vary over a range of less than an order of magnitude irrespective of a 2.3 eV change of the calculated I(p) of the alkynes; therefore, a rate-limiting single electron-transfer mechanism is unlikely. The participation of oxirene (oxene insertion) and metallaoxetene ([2 + 2] cycloaddition) intermediates appears to be implausible based on product analysis. A linear Hammett correlation was established using σ+ and σ(jj)(G) parameters for the cycloaddition of 1 with para-substituted aryl trimethylsilylacetylenes, and the rate-limiting vinyl radical intermediate formation is proposed.
Inverting Conventional Chemoselectivity in the Sonogashira Coupling Reaction of Polyhalogenated Aryl Triflates with TMS-Arylalkynes
Wang, Miao,So, Chau Ming
supporting information, p. 681 - 685 (2022/01/20)
A newly developed phosphine ligand with a C2-cyclohexyl group on the indole ring was successfully applied in a chemoselective Sonogashira coupling reaction with excellent chemoselectivity, affording an inversion of the conventional chemoselectivity order of C–Br > C–Cl > C–OTf. This study also provided an efficient approach to the synthesis of polycyclic aromatic hydrocarbons (PAHs) and the natural product analogue trimethyl-selaginellin L by merging of chemoselective Sonogashira and Suzuki–Miyaura coupling reactions.
Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
Luo, Xiaosheng,Wang, Ping
supporting information, p. 4960 - 4965 (2021/07/20)
Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
Synthesis of Phenanthrenes via Palladium-Catalyzed Three-Component Domino Reaction of Aryl Iodides, Internal Alkynes, and o-Bromobenzoic Acids
Deng, Guobo,Liang, Yun,Luo, Xiai,Yang, Xiumei,Yang, Yuan,Yang, Yuzhong,Zhou, Liwei
supporting information, p. 1223 - 1230 (2020/04/15)
A new palladium-catalyzed domino alkyne insertion/C-H activation/decarboxylation sequence has been developed, which provides an efficient approach for synthesizing a variety of functionalized phenanthrenes in moderate to good yields. The method shows broad substrate scope and good functional group tolerance by employing readily available materials, including aryl iodides, internal alkynes, and o-bromobenzoic acids, as three-component coupling partners.