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Molybdenum propargyl complex

Z,Z)-l,4-Dialkoxy-l,3-dienes can be readily prepared from propargyl ethers and molybdenum carbene complexes (equation 185)307. High stereoselectivity in this reaction may be due to the formation of stable vinyl hydride complex with the enol ether. [Pg.465]

Molybdenum imido alkylidene complexes have been prepared that contain bulky carboxylate ligands such as triphenylacetate [35]. Such species are isola-ble, perhaps in part because the carboxylate is bound to the metal in an r 2 fashion and the steric bulk prevents a carboxylate from bridging between metals. If carboxylates are counted as chelating three electron donors, and the linear imido ligand forms a pseudo triple bond to the metal, then bis(r 2-carboxylate) species are formally 18 electron complexes. They are poor catalysts for the metathesis of ordinary olefins, because the metal is electronically saturated unless one of the carboxylates slips to an ri1 coordination mode. However, they do react with terminal acetylenes of the propargylic type (see below). [Pg.23]

CH2=C=CPh)] (39b). The latter two complexes display very similar structural characteristics. Both complexes contain hydrocarbyl ligands in which i/(CH2-C) exceeds /(C-CR). For instance, in the molybdenum complex these distances are 1.380(2) A and 1.263(4) A, whereas those reported by Wojcicki are 1.39(2) and 1.23(1) A. Such data were interpreted in terms of a large contribution from the 17 -propargyl resonance structure [105(1) and 39(1)), respectively]. However, values of 7ch indi-... [Pg.86]

The formation of 1,5-diyne complexes as side-products in some reactions of cations 92 with metal alkyls [41] and the facile, regioselective reduction of a propargylic chloride complex by Zn/HOAc, used in the synthesis of the insect pheromone 5-(Z)-tetradecenyl acetate [221], provided early evidence for the intermediacy of (propargyl)Co2(CO)5 mdicals. In a similar vein, the binuclear molybdenum-complexed propargyl cations react with Na/Hg to produce... [Pg.127]

Propargyl alcohols add to allylic indium sesquihalides, but the mechanism of the process is not known. Molybdenum complexes have been used to cyclize enynes and dienynes . ... [Pg.506]

Propargyl alcohols can be converted into vinyl iodides and bromides using a dual catalyst approach (Scheme 7.119) [183]. The combination of a common gold complex with a molybdenum species generated a highly active catalyst for this reaction. The precise... [Pg.637]


See other pages where Molybdenum propargyl complex is mentioned: [Pg.242]    [Pg.242]    [Pg.73]    [Pg.251]    [Pg.294]    [Pg.254]    [Pg.201]    [Pg.109]    [Pg.516]    [Pg.151]    [Pg.379]    [Pg.145]    [Pg.150]   


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Propargyl complexes

Propargylic complexes

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