We have developed a nickel-catalyzed transformation, in which phthalimides react with trimethylsilyl-substituted alkynes in the presence of Ni(0)/PMe3/MAD catalyst to provide isoindolinones. The reaction process displays an unusual mechanistic feature-decarbonylation and alkylidenation. The use of both trimethylsilyl-substiuted alkynes and MAD was found to be essential for the transformation with high selectivities.
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http://dx.doi.org/10.1021/ja4068172 | DOI Listing |
RSC Adv
December 2021
The reaction of trimethylsilyl-substituted alkynes with 0.5 equivalents of CpZrCl and 1 equivalent of EtAl in toluene at room temperature for 18 hours gives, after hydrolysis/deuterolysis or iodination, functionalized products of the homo-coupling of silyl-substituted alkynes in good yield. Trimethylsilyl-substituted α,ω-diynes react with the CpZrCl - EtAl reagent system to give (1,2)-1,2-bis(iodo(trimethylsilyl)methylene)cycloalkanes after iodinolysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2018
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077-, Göttingen, Germany.
The synthesis of a series of 5-(alkynyl) dibenzothiophenium triflates, prepared from dibenzo[b,d]thiophene 5-oxide and the corresponding trimethylsilyl-substituted alkynes is reported. Their structures were determined by X-ray crystallography, and their reactivities as electrophilic alkynylation reagents evaluated. Their broad substrate scope and functional-group tolerance illustrate their potential to become an alternative to the broadly used EBX reagents.
View Article and Find Full Text PDFJ Am Chem Soc
September 2016
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Multisubstituted tropanes and indolizidines have been prepared with high regio- and stereoselectivity by the [3+2] cycloaddition of unstabilized azomethine ylides generated from readily prepared trimethylsilyl-substituted 1,2-dihydropyridines via protonation or alkylation followed by desilylation. Starting from 1,2-dihydropyridines bearing a ring trimethylsilyl substituent at the 6-position, an intermolecular alkylation/desilylation provides endocyclic unstabilized ylides that successfully undergo cycloaddition with a range of symmetrical and unsymmetrical alkyne and alkene dipolarophiles to afford densely substituted tropanes incorporating quaternary carbons in good yields and with high regio- and stereoselectivity. Additionally, an intramolecular alkylation/desilylation/cycloaddition sequence provides convenient and rapid entry to bridged tricyclic tropane skeletons, allowing for five contiguous carbon stereocenters to be set in a single experimental operation and under mild conditions.
View Article and Find Full Text PDFOrg Lett
April 2015
Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
The cobalt-catalyzed Diels-Alder reaction of trimethylsilyl-substituted alkynes with 1,3-dienes led to dihydroaromatic intermediates which were transformed into iodobenzene derivatives. For this transformation, the dihydroaromatic intermediates had to be oxidized and the trimethylsilyl-substituted arene had to undergo a silicon-iodine exchange reaction. For this purpose, a number of oxidizing agents and iodonium sources were tested in order to realize the desired two transformations in a single step.
View Article and Find Full Text PDFJ Am Chem Soc
December 2014
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, P. R. China.
A three-coordinate cobalt(I) complex exhibits high catalytic efficiency and selectivity as well as good functional group compatibility in alkyne hydrosilylation. [Co(IAd)(PPh3)(CH2TMS)] (1) (IAd = 1,3-diadamantylimidazol-2-ylidene) facilitates regio- and stereoselective hydrosilylation of terminal, symmetrical internal, and trimethylsilyl-substituted unsymmetrical internal alkynes to produce single hydrosilylation products in the forms of β-(E)-silylalkenes, (E)-silylalkenes, and (Z)-α,α-disilylalkenes, respectively, in high yields. The comparable catalytic efficiency and selectivity of the Co(I) silyl complex [Co(IAd)(PPh3)(SiHPh2)] that was prepared from the reaction of 1 with H2SiPh2, and the isolation of an alkyne Co(I) complex [Co(IAd)(η(2)-PhC≡CPh)(CH2TMS)] from the reaction of 1 with the acetylene, point out a modified Chalk-Harrod catalytic cycle for these hydrosilylation reactions.
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