32904-87-3Relevant academic research and scientific papers
Bifunctional phosphine ligand-enabled gold-catalyzed direct cycloisomerization of alkynyl ketones to 2,5-disubstituted furans
Hu, Xiaojun,Zhou, Bingwei,Jin, Hongwei,Liu, Yunkui,Zhang, Liming
supporting information, p. 7297 - 7300 (2020/07/14)
An efficient synthesis of 2,5-disubstituted furans directly from alkynyl ketones has been developed via tandem gold(i)-catalyzed isomerization of alkynyl ketones to allenyl ketones and cycloisomerization. The key to the success of this chemistry is the use of a biphenyl-2-ylphosphine ligand featuring a critical remote tertiary amino group.
Alkynyl?B(dan)s in Various Palladium-Catalyzed Carbon?Carbon Bond-Forming Reactions Leading to Internal Alkynes, 1,4-Enynes, Ynones, and Multiply Substituted Alkenes
Tani, Tomohiro,Sawatsugawa, Yuuki,Sano, Yusuke,Hirataka, Yo,Takahashi, Naomi,Hashimoto, Sadahiro,Sugiura, Tetsuya,Tsuchimoto, Teruhisa
, p. 1815 - 1834 (2019/03/07)
It was found that the C(sp)?B(dan) bond of alkynyl?B(dan)s can be directly used for palladium-catalyzed carbon?carbon bond-forming reactions with aryl(alkenyl) halides and allylic carbonates as electrophiles, thus delivering unsymmetrical internal alkynes and unconjugated 1,4-enynes, respectively. With acyl chlorides as electrophiles, ynone synthesis is also promoted by a palladium catalyst with the assistance of a copper co-catalyst. These reactions can be achieved as more convenient one-pot reactions, without isolating the alkynyl?B(dan) formed in situ by the zinc-catalyzed dehydrogenative borylation of alkynes with HB(dan). In addition to direct C(sp)?B(dan) bond transformations, the C≡C bond in an alkynyl?B(dan) proved to be a promising scaffold for the construction of a multisubstituted alkene, which is synthesized by diboration of the C≡C?B(dan) moiety, leading to a triborylalkene followed by iterative regio- and stereoselective Suzuki?Miyaura cross-coupling reactions. As one example, the synthesis of the ethene with four different aryl groups, p-MeC6H4, p-MeOC6H4, p-NCC6H4, and p-F3CC6H4, was attained in high overall yield of 64% in six steps starting from the terminal alkyne, p-MeC6H4C≡CH. Besides these synthetic applications of the alkynyl?B(dan), the scope of the alkynyl substrate in the zinc-catalyzed dehydrogenative borylation was expanded to enhance the reliability as a provider of the alkynyl?B(dan). Consequently, 42 alkynes were found to participate in the dehydrogenative borylation as substrates; these are alkyl-, alkenyl-, aryl-, heteroaryl-, ferrocenyl-, silyl-, and borylalkynes, with or without a variety of functional groups. Lastly, a new method for preparing HB(dan), as a sulfide-free, cost-saving, and reaction-time-saving route, is disclosed. (Figure presented.).
A polymer electrolyte fuel cell
-
, (2007/10/13)
PROBLEM TO BE SOLVED: To provide a polymerelectrolyte type fuel cell equipped with a separator plate which can make a proportion of a flow in a gas flow path within an electrode plane to an infiltration flow even to realize stable gas supply. SOLUTION: Submanifolds 18a, 19b increased in sectional area are formed at portions of a gas flow path 17 of a separator plate 11, whereby a gas can be evenly supplied to do away with power generation distribution within an electrode plane and achieve good stability and high efficiency of the fuel cell. COPYRIGHT: (C)2004,JPO
Electrophilic cyclization of 4-thio-but-2-yn-1-ols via 1,2-migration of the thio group: efficient synthesis of 2,4-dihalo-3-thio-substituted furans
Zhou, Hongwei,Yao, Jinzhong,Liu, Guoliang
, p. 226 - 228 (2008/03/30)
A facile and efficient method for the synthesis of 2,4-dihalo-3-thio-furans via the electrophilic cyclization and 1,2-migration of the thio group of 4-thio-but-2-yn-1-ols was developed. As a result of the ready availability of starting materials and the s
