Deoxygenation of 1,4-epoxides by Grignard reagents
摘要:
Freshly prepared Grignard reagents in refluxing THF smoothly deoxygenate benzo-fused 1,4-dihydro-1,4-epoxides to afford the corresponding naphthalenes and anthracenes in good yields. (C) 1997 Elsevier Science Ltd.
The present invention relates to a-amino boronic acid derivatives. These compounds are useful for inhibiting the activity of immunoproteasome (LMP7) and for the treatment and/or prevention of medical contidions affected by immunoproteasome activity such as inflammatory and autoimmune diseases, neurodegenerative diseases, proliferative diseases and cancer.
CpRuCl(PPh<sub>3</sub>)<sub>2</sub>-Catalyzed Cyclopropanation of Bicyclic Alkenes with Tertiary Propargylic Acetates
作者:Alphonse Tenaglia、Sylvain Marc
DOI:10.1021/jo060276a
日期:2006.4.1
The electron-rich cyclopentadienylruthenium complex CpRuCl(PPh3)2 turns out to be an efficient catalyst for the regio- and stereoselective cyclopropanation of bicyclic alkenes with tertiary propargylic carboxylates. The reaction provides 1,2,3-trisubstituted cyclopropanes in high yields as a single stereoisomer instead of the expected cyclobutenes via [2 + 2] cycloaddition. Functional groups such as
A New and Efficient Hypervalent Iodine−Benzyne Precursor, (Phenyl)[<i>o</i>-(trimethylsilyl)phenyl]iodonium Triflate: Generation, Trapping Reaction, and Nature of Benzyne
the reaction in the presence of furan indicates a quantitative generation of benzyne and its efficient capture by the furan. Similarly, methylbenzynes (22 and 27) are efficiently generated from the corresponding methyl-substituted (trimethylsilyl)phenyliodonium triflates (12 and 13). The preparation of the hypervalent iodine−benzyne precursors, the generation of benzynes, the trapping reactions, and
Mechanistic Studies of the Palladium-Catalyzed Ring Opening of Oxabicyclic Alkenes with Dialkylzinc
作者:Mark Lautens、Sheldon Hiebert、Jean-Luc Renaud
DOI:10.1021/ja010498k
日期:2001.7.1
The mechanism of the palladium-catalyzed ring opening of oxabicyclicalkenes with dialkylzinc has been studied. Experiments which rule out a π-allyl mechanism were carried out. Trapping carbometalated products and synthesis and successful reaction of alkyl palladium species provided strong evidence in favor of an enantioselective carbopalladation as the key step in the mechanism. The studies also suggest
Copper-Catalyzed Ring-Opening of Heterobicyclic Alkenes with Grignard Reagents: Remarkably High<i>anti</i>-Stereocontrol
作者:Ramón Gómez Arrayás、Juan Carlos Carretero、Silvia Cabrera
DOI:10.1055/s-2006-926379
日期:——
protocols for the ring-opening reaction of heterobicyclic alkenes with carbon nucleophiles which typically occur with syn selectivity, the alkylative ring-opening reaction of [2.2.1]oxa- and azabicyclicalkenes with Grignard reagents in the presence of a catalytic amount of copper(I) takes place with very high or complete anti-stereocontrol under smooth reaction conditions. This new procedure proved to