Allyl-type

Figure 27. Top One of the allylic type-VI structures, formed by in-phase combination of type-V structures, Bottom The 6ve type-VI structures,...

The energies of this Cl and of the other ones calculated in this work are listed in Table III. The calculated CASSCF values of the energies of the two lowest electronically states are 9.0 eV (5i, vertical) and 10.3 eV ( 2, vertical) [99]. They are considerably higher than the expenmental ones, as noted for this method by other workers [65]. In all cases, the computed conical intersections lie at much lower energies than the excited state, and are easily accessible upon excitation to Si. In the case of the H/allyl Cl, the validity confirmation process recovered the CHDN and 1,3-CHDN anchors. An attempt to approach the third anchor [BCE(I)] resulted instead in a biradical, shown in Figure 43. The bhadical may be regarded as a resonance hybrid of two allyl-type biradicals. 

Trifluoromethyl-substituted 1,3-dipoles of the allyl type. Trifluoromethyl-substituted azomethine imines ate readily available on reaction of hexafluo-... 

Regioselectivity in reactions of heterocyclic anions of allyl-type with electrophiles 99CRV665. 

Regioselectivity of syntheses of heterocycles in reactions of allyl-type anions with electrophiles 99CRV665. 

Selective reactions of minor tautomers of allylic type triorganoboranes, among them cyclic triorganoboranes 99JOM(581)98. 

Volume E21 D. 1.3.3.1. Addition of Allyl-Type Organometallic Compounds General Aspects 1357... 

Formation of C-C Bonds by Addition of Allyl-Type Organometallic Compounds to Carbonyl Compounds... 

The allylic-type furylic radical 6 is resonance stabilized to such a degree that its reactivity in promoting propagation by adding onto another furan ring is minimal. The fate of these radicals will simply be to couple with another radical present in the reaction medium (primary or secondary) or to disproportionate to regenerate the furan character of the ring26. ... 

During the synthesis of functional disiloxanes via hydrosilation, the starting materials are usually either tetramethyldisiloxane or dimethylchlorosilane and a proper olefinic (mostly allyl type) compound having the desired functional end group. If dimethylchlorosilane is employed, the hydrosilation is usually followed by hydrolysis. As a specific example, the synt hesis of 1,3-bis(3-glycidoxypropyl)tetramethyldisiloxane is shown in Reaction Scheme IV. 

As far as the reactions with benzyl chlorides are concerned (74), the oxidative addition of benzyl chloride and substituted benzyl chlorides to palladium atoms yields rj -benzylpalladium chloride dimers. The parent compound, bis(l,2,3-7 -benzyl)di-/i,-chloro-palladium(II), quantitatively adds four molecules of PEts by first forcing the rj -benzyl-iy -benzyl transformation, with subsequent breakage of the Pd-Cl bridges to form trans-bistPEtsKbenzyDchloroPddI). The spectral characteristics of the parent molecule are indicative of the allylic type of bonding. Similar i7 -benzyl compounds were formed from 4-methylbenzyl chloride, 2-chloro-l,l,l-trifluoro-2-phenylethane, and 3,4-dimethylbenzyl chloride. 

Notably, the bicyclic radical 41 is localized, in sharp contrast to the allylic-type delocalization of cyclotrigermenyl radical 39 and cyclotetrasilenyl radical 40. The obvions reason for snch a distinction is the absence of the neighboring to the Ge-radical center tt-bond necessary for the effective throngh-bond delocalization of the unpaired electron in the radical 41, whereas the through-space radical-C=C bond interaction is not sufficiently strong to indnce the effective delocalization of the unpaired electron. 

The four-membered ring of 66 [Li (dme)3] was perfectly planar with two pairs of distinctly different skeletal Ge-Ge bonds of 2.5116(6) and 2.3679(6) A the former is typical for the Ge-Ge single bonds, whereas the latter is close to the valnes of Ge=Ge double bonds. Such crystallographic features led to the formulation of the allylic-type strncture of 66 , in which the negative charge is delocalized over the Gej fragment of the four-membered ring. 

On the other hand, radicals are undoubtedly involved in the photodegradation of PVC under some experimental conditions. Recent ESR studies have provided evidence for the formation of alkyl and allyl-type radicals during the low-temperature UV irradiation of the polymer (43,72,87). Peroxy radicals were also observed when molecular oxygen was present (43,87). Other ESR work has shown convincingly that the radical -CHCI-CH2-CH-CH2-CHCI- results from the irradiation of PVC at liquid-nitrogen temperature (61,93) and is converted into a -CH2-CC1-CH2- radical at -110°C (93). 

The polymerization of conjugated dienes with transition metal catalytic systems is an insertion polymerization, as is that of monoalkenes with the same systems. Moreover, it is nearly generally accepted that for diene polymerization the monomer insertion reaction occurs in the same two steps established for olefin polymerization by transition metal catalytic systems (i) coordination of the monomer to the metal and (ii) monomer insertion into a metal-carbon bond. However, polymerization of dienes presents several peculiar aspects mainly related to the nature of the bond between the transition metal of the catalytic system and the growing chain, which is of o type for the monoalkene polymerizations, while it is of the allylic type in the conjugated diene polymerizations.174-183... 

These co-iodinated cotelomers were functionalized into vinyl or allyl type olefins by two different two-step processes as follow17,18 ... 

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