Scope of Palladium-Catalyzed Alkylative Ring Opening
作者:Mark Lautens、Sheldon Hiebert
DOI:10.1021/ja037550s
日期:2004.2.1
We have explored the scope of the palladium-catalyzed nucleophilic ringopening methodology. New highly selective and highly active catalysts have been found for the ringopening of oxabenzonorbornadienes. Employing these catalysts, the addition of various alkyl nucleophiles to oxabenzonorbornadiene has been achieved. In addition, reaction of diethylzinc with [3.2.1] oxabicyclic alkenes has been accomplished
Bicyclic alkenes 1a-e and 5 undergo [2 + 2] cycloaddition with a variety of alkynes PhC(triple bond)CPh, (TMS)C(triple bond)CH, HC(triple bond)C(CH(3))(2)OH, (TMS)C(triple bond)CCO(2)Et, PhC(triple bond)CCH(3), C(2)H(5)C(triple bond)CC(2)H(5), CH(3)C(triple bond)CC(3)H(7), and CH(3)C(triple bond)CC(2)H(5) in the presence of Co(PPh(3))(2)I(2), PPh(3), and Zn powder in toluene to afford the corresponding
Generation of Arynes Using Trimethylsilylmethyl Grignard Reagent for Activation of <i>ortho</i>-Iodoaryl or <i>ortho</i>-Sulfinylaryl Triflates
作者:Suguru Yoshida、Keisuke Uchida、Takamitsu Hosoya
DOI:10.1246/cl.150060
日期:2015.5.5
The trimethylsilylmethyl Grignard reagent triggered efficient generation of arynes from various ortho-iodoaryl or ortho-sulfinylaryl triflates. The moderate nucleophilicity and basicity of the reagent facilitated efficient reactions between the aryne precursors and arynophiles containing organometallic nucleophile-sensitive functionalities.
The allylation of heterobicyclicalkenes is presented for the first time. By using an inexpensive cobalt salt as the catalyst and easy‐to‐handle potassium allyltrifluoroborate as the reagent, an unprecedented formal hydroallylation of the bicyclic alkenes is realized in high efficiency. When a chiral cobalt/bis(phosphine) complex is used instead, the alternative ring‐opening products can be obtained
Remote Electronic Effects in the Rhodium-Catalyzed Nucleophilic Ring Opening of Oxabenzonorbornadienes
作者:Mark Lautens、Gavin A. Schmid、Anh Chau
DOI:10.1021/jo025822o
日期:2002.11.1
We report the application of our rhodium-catalyzednucleophilic ring-opening methodology to unsymmetrically arene-substituted oxabenzonorbornadienes. The regioselectivity of the ringopening was investigated using a variety of nucleophiles that led to a broad selection of dihydronaphthalene products. It was found that good to excellent regioselectivities are obtained using strongly pi-donating substituents