Polyfunctionalized

Highly selective synthesis of polyfunctionalized heterocycles based on ring expansion of squaric acid derivatives 97YGK785, 98SL1167. 

The Michael addition of nih oalkanes to alkenes substituted with two elecbon-withdrawing groups at the a- and 3-positions provides a new method for the preparation of functionalized alkenes. Although reactions are not new, Ballini and coworkers have used this sbategy in the synthesis of polyfunctionalized unsaturated carbonyl derivatives by Michael addition of nih oalkanes to enediones as shown in Eqs. 7.124-7.126. Success of this type of reaction depends on the base and solvent. They have found that DBU in acetonihile is the method of choice for this puipose. This base-solvent system has been used widely in Michael additions of nitroalkanes to elechon-deficient alkenes (see Section 4.3, which discusses the Michael addition). ... 

Radical-based carbonylation procedures can be advantageously mediated by (TMSlsSiH. Examples of three-component coupling reactions are given in Reactions (74) and (75). The cascade proceeds by the addition of an alkyl or vinyl radical onto carbon monoxide with formation of an acyl radical intermediate, which can further react with electron-deficient olefins to lead to the polyfunctionalized compounds. ... 

Polyfunctionality of the reactants is not sufficient in itself to assure formation of polymer the reaction may proceed intramolecularly with the formation of cyclic products. For example, hydroxy acids when heated yield either lactone or linear polymer (or both),... 

Scheme 1. The concept of polyfunctionality of a nanocomposite obtained from a nanostructured metal (0) and a cross-linked functional polymer.

The exceptional mildness of Nugent s and RajanBabu s system was demonstrated by Grande et al. in a synthesis of polyfunctionalized carbacephems as shown in Scheme 21. The sensitive -lactam and the other functional groups are readily tolerated by Cp2TiCl [ 100]. 

Wallace H. Carothers. Polymers and Polyfunctionality. Transactions of the Faraday Society. 32 (1936) 39-53. Carothers Cambridge speech is the source for polymers providing the bulk of living things Collins cauliflower mass and no mention of nylon. 

Hesse691 has shown that the unimolecular chemistry of cation radicals of di- or polyfunctionalized alkanes is strongly dependent upon the interaction of the functional groups, mainly via neighbouring group participation in the transition states and the... 

A very important development in multicomponent domino reactions is the enan-tioselective approach using organocatalysts which has been recently discussed in an excellent review by Yus and Ramon [2c]. The latest great success in this field stem from Enders and coworkers, presence of an enantiopure proline derivative to give polyfunctionalized cyclohexenes with 99% ee [111]. 

Polyfunctionalized nitro compounds are prepared by the Michael addition using 2-alkenyl-substituted 2-siloxycyclopropanecarboxylates as Michael acceptors (Eq. 4.120).165... 

Microwave-induced 1,3-dipolar cycloadditions involving azomethine ylides have been widely reported in the literature. Bazureau showed that imidates derived from a-amino esters 120, as potential azomethine ylides, undergo 1,3-dipolar cyclo-additions with imino-alcohols 121 in the absence of solvent under microwave irradiation. This reaction leads to polyfunctionalized 4-yliden-2-imidazolin-5-ones 122 (Scheme 9.36) [87]. 

Finally, Lipshutz and co-workers developed catalytic copper(i)-assisted polyfunctionalizations of zirconacyclopen-tenes of type 93 by trapping the intermediary zirconium enolates 94 with an aldehyde to form the corresponding 2,3-disubstituted cyclopentanones 95 (Scheme 40).146... 

By functionalizing the end groups according to way (2) (Figure 10) polyfunctionalized dendrimers can be achieved in which the end groups of the dendrimer are connected to functional moieties in one synthetic step. Not least of all because of the... 

This reaction has been extensively used for the synthesis of polyfunctionalized piperidines with a wide range of nucleophiles selected and representative examples are collected in Table 15. From these results, hydrides, Grignard reagents, aluminium derivatives, allylsilane, as well as aromatics can be used as nucleophiles to give the corresponding C-8a functionalized compounds in good yields and, in most cases, excellent selectivities. 

One may note that the titration of the humic acid - because of its polyfunctionality - is less steep than that of the acetic acid-phenol mixture. 

The selective functionalization of saccharose and sorbitol with fatty acids for the construction of a perfect amphiphilic structure cannot be realized in simple technical processes because of the polyfunctionality of the molecule. This is why the products offered on the market contain different amounts of mono-, di- and... 

Zhong Y-W, Matsuo Y, Nakamura E (2006) Convergent synthesis of a polyfunctionalized fullerene by regioselective five-fold addition of a functionalized organocopper reagent to C60. Org. Lett. 8 1463-1466. 

A tandem ring-opening of 3,4- and 3,6-dilithiated thienothiophenes has been used to synthesize polyfunctionalized enediynes (e.g. Scheme 9). ... 

Functionalized propargyUc organolithium compounds are probably involved in the transformation of chlorinated ethers or amines 211 into polyfunctionalized products 212, which were achieved through a DTBB-catalyzed lithiation under Barbier-type reaction conditions (Scheme 73). The reaction failed for the corresponding thioethers (Y =... 

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