Water Control over the Chemoselectivity of a Ti/Ni Multimetallic System: Heck- or Reductive-Type Cyclization Reactions of Alkyl Iodides
摘要:
A versatile Ti/Ni multimetallic protocol is described for the efficient catalysis of two different reactions, namely a Heck- and reductive-type cyclization of alkyl iodides, in the absence or presence of water, respectively. Noteworthy, the versatility of Ti(III) chemistry allows an oxidative ending step under reductive conditions to give Heck-type products, and the good H-atom transfer capabilities of Ti(III)-aqua complexes ensure reductive-type cyclizations.
Single-Electron-Transfer Strategy for Reductive Radical Cyclization: Fe(CO)<sub>5</sub> and Phenanthroline System
作者:Joon Young Hwang、Jong Hwa Baek、Tae Il Shin、Jung Ha Shin、Jae Won Oh、Kwang Pyo Kim、Youngmin You、Eun Joo Kang
DOI:10.1021/acs.orglett.6b02375
日期:2016.10.7
electron-transfer strategy using low-valent iron pentacarbonyl [Fe(CO)5] to generate radical species from alkyl iodides was achieved. A range of pyrrolidines, tetrahydrofurans, and carbocycles were synthesized via 5-exo cyclization reactions of alkyl radical intermediates generated by electron transfer from a system involving Fe(CO)5, 1,10-phenanthroline, and diisopropylamine. Moreover, tandem addition
Iron-Catalyzed Tandem Cyclization and Cross-Coupling Reactions of Iodoalkanes and Aryl Grignard Reagents
作者:Jae Gon Kim、Young Hoon Son、Jin Won Seo、Eun Joo Kang
DOI:10.1002/ejoc.201403511
日期:2015.3
Several experimental results, such as cyclopropyl ring opening, the stereochemical outcome of the reaction with a secondary iodide substrate, and intermediate identification with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), support the conclusion that a radical process is involved in this catalytic system. Moreover, deuterium labeling experiments indicated that radical disproportionation could occur in
A photochemically promoted intramolecular cyclization of aryl-, vinyl-, and alkyliodo allenes has been developed. The optimal conditions employed [Ir(ppy)2(dtbbpy)]PF6 (1 mol%) as catalyst affording products with high exo selectivity in moderate to good yields. Chiral substrates showed diastereoselectivity of up to 95/5 favoring trans product.
A palladium-catalyzed, photochemical tandem cyclization/dicarbofunctionalization of unactivated alkyl halides containing an alkene moiety offers an appealing route to produce five- or six-membered rings in a redox-neutral fashion. Multisubstituted carbo- and heterocyclic compounds were prepared through the formation of new C–B or C–O bonds, which provides a convenient synthetic route for further transformations
[EN] RUTHENIUM COMPLEXES FOR USE IN OLEFIN METATHESIS<br/>[FR] COMPLEXES DE RUTHÉNIUM DESTINÉS À ÊTRE UTILISÉS DANS LA MÉTATHÈSE D'OLÉFINES
申请人:UNIV ST ANDREWS
公开号:WO2011117571A1
公开(公告)日:2011-09-29
Cis ruthenium complexes that can be used as catalysts are described. The complexes are generally square pyramidal in nature, having two anionic ligands X adjacent to each other. The complexes can be used as catalysts, for example in olefin metathesis reactions. Corresponding trans ruthenium complexes are also described, together with cationic complexes where one or both of the anionic ligands X are replaced by a non- co-ordinating anionic ligand.