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Allyl hetero compounds

Similar to the P450s, these reactions are often stereospecific and include hetero-atom oxidations, epoxidation, and oxidation of C-H bonds in allylic/benzylic compounds, alcohols, and indole [59]. [Pg.227]

Allyl sulfides and allyl amines. Rhodium-catalyzed decomposition of ethyl diazoacetate in the presence of these allyl compounds generates products 136 and 137, respectively, derived from [2,3] rearrangement of an S- or N-ylide intermediate, besides small amounts of carbene dimers No cyclopropane and no product resulting from the ylide by [1,2] rearrangement were detected. Besides RhjfOAc) and Rhg(CO)i6, the rhodium(I) catalysts [(cod)RhCl]2 and [(CO)2RhCl]2 were found to behave similarly, but yields with the only allyl amine tested, CH =CH—CH NMe, were distinctly lower with the latter two catalysts. Reaction temperatures are higher than usually needed in rhodium-promoted diazoalkane decomposition, which is certainly due to competition between the diazo compound and the allylic hetero-... [Pg.135]

We chose reaction 3, the 1,3 dipolar cycloaddition, to test out hetero reaction generation procedure. By introducing the elements carbon, nitrogen and oxygen into the reaction centres of the 1,3 dipole we generated all conceivable allyl type compounds. Unfortunately the structures (shown in Figure 7) are known and they had all been used in 1,3 dipolar additions. Thus our hope to find a new 1,3 dipole was lost. [Pg.389]

Benzyl-type carbanions and their metallo compounds, derived from aromatic or hetero-aromatic precursors, bearing carbon- or hetero-substituents, are readily available with variable substitution patterns due to their mesomeric stabilization (see Section 1.3.2.2)2. Even dicarbanions are accessible without difficulty3,4. The equilibrium acidities of many aromatic hydrocarbons have been determined5-7. The acidities of a-hetero-substituted toluenes8 are similar to those of the corresponding allylic compounds and can usually be generated by the same methods. [Pg.185]

Allyl anion synthons A and C, bearing one or two electronegative hetero-substituents in the y-position are widely used for the combination of the homoenolate (or / -enolate) moiety B or D with carbonyl compounds by means of allylmetal reagents 1 or 4, since hydrolysis of the addition products 2 or 5 leads to 4-hydroxy-substituted aldehydes or ketones 3, or carboxylic acids, respectively. At present, 1-hetero-substituted allylmetal reagents of type 1, rather than 4, offer the widest opportunity for the variation of the substitution pattern and for the control of the different levels of stereoselectivity. The resulting aldehydes of type 3 (R1 = H) are easily oxidized to form carboxylic acids 6 (or their derivatives). [Pg.226]

A regio- and diastereoselective Pd-catalyzed domino silastannylation/allyl addition of allenes 6/1-236 containing a carbonyl moiety with Bu3Sn-SiMe3 6/1-237 is described by Kang and coworkers [117]. The reaction allows the synthesis of hetero-and carbocyclic compounds with a ring size of five and six. It can be assumed that... [Pg.397]

It is reasonable to assume, that the counterion prefers to coordinate to the carbon atom with the highest electron density. Hence, according to this crude picture, donor-substituted allylmetallics are to be regarded as 3-metalated hetero-substituted vinyl compounds, acceptor-substituted ones on the other hand as 1-metalated hetero-substituted allyl compounds. [Pg.679]

Internal complexation has to be considered additionally as chelating substituents may alter the situation completely. For example, in the lithiated allyl A,A-diisopropylcarbamate 3 possessing a delocalized structure, it is clearly a 1-lithiated hetero-substituted allyl compound despite the fact that oxygen is a donor and the silyl group can be regarded more as an acceptor13. [Pg.679]

Once regiocontrol was achieved, donor-substituted allyl metallics found two synthetically important applications. The hetero-substituted vinyl compounds, obtained by alkylation of a substituted allyl carbanion in the 3-position ( ), can be hydrolyzed to carbonyl compounds substituted on the /1-carbon atom. Thus, the substituted allyl carbanion was used as an equivalent of the homoenolate synthon18 19. [Pg.680]

Hetero-substituted allyl compounds obtained by electrophilic attack in the 1-position can be reduced to give the heteroalkyl compounds carrying the new substituent on the a-carbon atom ( ). In this case, the double bond was used as an activating substituent only, to achieve easier deprotonation and higher nucleophilicity. In both cases the synthetically important umpolung of reactivity was achieved20. [Pg.680]

Allyl amines can also be formed in an oxidative environment. Nicholas et al. have shown that instead of phenyl hydroxylamine as the nitrogen donor, it is possible using f-BuOOH as the terminal oxidant and the molybdenum catalyst described above [65]. The procedure is analogues to the in situ hetero-Diels-Alder reaction of nitroso compounds developed earlier by others [66]. [Pg.33]

The remarkable affinity of the silver ion for hahdes can be conveniently applied to accelerate the chiral palladium-catalyzed Heck reaction and other reactions. Enantioselectivity of these reactions is generally increased by addition of silver salts, and hence silver(I) compounds in combination with chiral ligands hold much promise as chiral Lewis acid catalysts for asymmetric synthesis. Employing the BINAP-silver(I) complex (8) as a chiral catalyst, the enantioselective aldol addition of tributyltin enolates (9) to aldehydes (10) has been developed." This catalyst is also effective in the promotion of enantioselective allylation, Mannich, ene, and hetero Diels-Alder reactions. [Pg.4490]

Summary Two catalytic reactions, i.e. silylative coupling (mms-silylation) (SC) catalyzed by complexes containing or generating Ru-H and/or Ru-Si bonds (I, II, V, VI) and cross-metathesis (CM) catalyzed by mthenium-carbene (i.e. 1st and 2nd generation mthenium Grubbs catalyst (ID, IV)) of vinyl and allyl-substituted hetero(N,S,B)organic compounds with conunercially available vinyltrisubstituted silanes, siloxanes, and silsesquioxane have been overviewed. They provide a universal route toward the synthesis of well-defined molecular compounds with vinylsilicon functionality. [Pg.416]

On the other hand, our recent study on the highly efficient cross-metathesis of vinyltrialkoxy-and vinyltrisiloxy-silanes with various olefins, for example, with styrene [12] allyl eth [13] and esters [14] as well as octavinylsilsesquioxane [IS] with several olefins have opened a new opportunity for the use of alkene-cross-metathesis in the synthesis of unsaturated organosilicon compounds (see also Refs. [5] and [6]). In this p r new examples of the two reactions involving hetero(N,S,B)organic olefins have been overviewed. [Pg.417]

Negishi, E.-i. Palladium-catalyzed cross-coupling involving 3-hetero-substituted compounds. Palladium-catalyzed a-substitution reactions of enolates and related derivatives other than the Tsuji-Trost allylation reaction. Handbook of Organopalladium Chemistry for Organic Synthesis 2002, 1, 693-719. [Pg.695]


See other pages where Allyl hetero compounds is mentioned: [Pg.137]    [Pg.185]    [Pg.144]    [Pg.144]    [Pg.415]    [Pg.416]    [Pg.353]    [Pg.272]    [Pg.506]    [Pg.861]    [Pg.270]    [Pg.598]    [Pg.199]    [Pg.310]    [Pg.207]    [Pg.160]    [Pg.20]    [Pg.923]    [Pg.758]    [Pg.758]    [Pg.569]    [Pg.575]    [Pg.594]    [Pg.1097]    [Pg.353]    [Pg.6]   


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Allyl compounds

Allyl hetero compounds 1,3-heteroatom-hydrogen transposition reaction

Allyl hetero compounds reduction

Allylic compounds

Allylic derivatives 3-hetero-substituted compounds

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