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Square planar, copper substitution

Helmchen and co-worker investigated the use of phosphinooxazolines as ligands for copper(II) catalyzed Diels-Alder reactions (Scheme 19) (214). Optimal selectivities are found for a-naphthyl-substituted phosphinooxazoline (299). These catalysts require 2.5 h to induce complete conversion to cycloadduct, compared to 18 h using the triflate complex 269c under identical conditions. Helmchen invokes a square-planar metal geometry to explain the stereochemistry of the adducts, similar to the model proposed by Evans. He suggests that the bulky phosphine substituents are required to orient binding of the dienophile in such a way as to place the olefin directly below the terf-butyl substituent on the oxazoline. [Pg.104]

Structural distortions and associated high lability often prevent kinetic data on substitution reactions of four-coordinate copper(II) compounds being obtained. Slightly distorted square-planar coordination is found for the copper complexes [CuXL] (L is AT-(2-(diethylamino)ethyl)salicylaldiminate, 6 X are monodentate anionic ligands or water), confirmed by X-ray analysis for X = NCS . The... [Pg.114]

See other pages where Square planar, copper substitution is mentioned: [Pg.155]    [Pg.174]    [Pg.755]    [Pg.832]    [Pg.243]    [Pg.24]    [Pg.360]    [Pg.98]    [Pg.41]    [Pg.214]    [Pg.321]    [Pg.71]    [Pg.557]    [Pg.681]    [Pg.201]    [Pg.23]    [Pg.291]    [Pg.204]    [Pg.176]    [Pg.432]    [Pg.3606]    [Pg.5535]    [Pg.323]    [Pg.326]    [Pg.357]    [Pg.471]    [Pg.450]    [Pg.290]    [Pg.240]    [Pg.63]    [Pg.66]    [Pg.305]    [Pg.340]    [Pg.212]    [Pg.212]    [Pg.131]    [Pg.3605]    [Pg.5534]    [Pg.1203]    [Pg.1327]    [Pg.25]    [Pg.233]    [Pg.182]    [Pg.371]    [Pg.1302]    [Pg.100]    [Pg.385]   
See also in sourсe #XX -- [ Pg.114 ]



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Square planar substitution

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