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Conjugation deficiency

Vogler H (1986) Structures and iH-Chemical SUfts of Conjugation Deficient Hydrocarbons. Int J Quant Chem 30 97... [Pg.293]

EKl Escherichia coli Certain conjugation-deficient E. coli mutants Filamentous bacteriophages... [Pg.137]

In a generalized sense, acids are electron pair acceptors. They include both protic (Bronsted) acids and Lewis acids such as AlCb and BF3 that have an electron-deficient central metal atom. Consequently, there is a priori no difference between Bronsted (protic) and Lewis acids. In extending the concept of superacidity to Lewis acid halides, those stronger than anhydrous aluminum chloride (the most commonly used Friedel-Crafts acid) are considered super Lewis acids. These superacidic Lewis acids include such higher-valence fluorides as antimony, arsenic, tantalum, niobium, and bismuth pentafluorides. Superacidity encompasses both very strong Bronsted and Lewis acids and their conjugate acid systems. [Pg.98]

In the coupling of the allenyl ester 7 with a terminal alkyne, an electron-deficient phosphine (Ph3P) gave the enyne-conjugated ester 8 as the major product, while an electron-rich phosphine (TDMPP or TTMPP) yielded the non-conjugated enyne esters ( )- and (Z)-9[4],... [Pg.451]

The coordination of the dienophile to a Lewis acid (in the calculations a proton was used as the Lewis acid) leads also to an increase in regioselectivity. The re-gioselectivity of reactions of electron-rich, or conjugated dienes, with electron-deficient dienophiles is also controlled hy the diene HOMO-dienophile LUMO interaction. From Fig. 8.2 it appears that the difference in magnitudes of the LUMO coefficients at carhon atoms 1 and 2 of acrolein (Ci -C2 = 0.20) is smaller than the same difference for protonated acrolein (Ci -C2 = 0.30-0.43) so that the reaction of the latter should he considerable more regioselective than the former in accordance with the experimental results [3]. [Pg.304]

Developing electron-deficient orbital Is stabilized by conjugation with jc-orbita in a planar arrangement... [Pg.734]

In the absence of heteroatom containing substituents (e.g. halo-, cyano-), at or conjugated with the radical center, carbon-centered radicals have nucleophilic character. Thus, simple alkyl radicals generally show higher reactivity toward electron-deficient monomers (eg. acrylic monomers) than towards electron-rich monomers (e.g, VAc, S) - Table 3.6. [Pg.113]

Olefin cross metathesis starts to compete with traditional C=C bondforming reactions such as the Wittig reaction and its modifications, as illustrated by the increasing use of electron-deficient conjugated alkenes for the ( )-selective construction of enals and enoates. [Pg.359]


See other pages where Conjugation deficiency is mentioned: [Pg.417]    [Pg.417]    [Pg.918]    [Pg.243]    [Pg.415]    [Pg.40]    [Pg.152]    [Pg.174]    [Pg.211]    [Pg.198]    [Pg.70]    [Pg.532]    [Pg.63]    [Pg.274]    [Pg.329]    [Pg.331]    [Pg.81]    [Pg.212]    [Pg.90]    [Pg.91]    [Pg.29]    [Pg.91]    [Pg.92]    [Pg.440]    [Pg.459]    [Pg.197]    [Pg.918]    [Pg.157]    [Pg.180]    [Pg.62]    [Pg.100]    [Pg.348]    [Pg.69]    [Pg.83]    [Pg.378]    [Pg.1042]    [Pg.1245]    [Pg.1325]    [Pg.53]    [Pg.73]    [Pg.205]    [Pg.312]   
See also in sourсe #XX -- [ Pg.350 ]




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Electron-deficient conjugated olefins

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