Formation of stable enols from 1,4-dilithio-1,3-dienes and acid chlorides by a de-aromatization/Michael addition/re-aromatization domino process

Hu, Qiaoshu; Wang, Chao; Li, Dongzhen; Xi, Zhenfeng

doi:10.1039/b705110g

Cited by 10 publications

(4 citation statements)

References 54 publications

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“…Another unexpected reaction of the dilithio reagent is shown in Scheme . To avoid the steric repulsion between the SiMe 3 group and the bulky R substituent derived from the acid chloride, the reactive species 31 takes the s-trans form instead of the s-cis conformation (Scheme ).…”

Section: Intermolecular Reactionsmentioning

confidence: 99%

“…29,30 Another unexpected reaction of the dilithio reagent is shown in Scheme 12. 31 To avoid the steric repulsion between the SiMe 3 group and the bulky R substituent derived from the acid chloride, the reactive species 31 takes the s-trans form instead of the s-cis conformation (Scheme 12). The C-Li bond in 31 then undergoes an intramolecular attack on the nearby phenyl substituent to give the stable enol derivatives 32 as final products.…”

Section: Dilithio Reagents Rarelymentioning

confidence: 99%

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1,4-Dilithio-1,3-dienes: Reaction and Synthetic Applications

2010

Acc. Chem. Res.

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124

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The development of organometallic reagents remains one of the most important frontiers in synthetic chemistry. Commonly used organometallic reagents (such as RLi and RMgBr) are typically monometallic compounds, although they aggregate in many cases. When two carbon-metal bonds are in the same molecule in close proximity, however, these two carbon-metal moieties may exhibit novel reactivity. In this Account, we outline our work on new reactions and synthetic applications of the organo-dilithio reagents 1,4-dilithio-1,3-butadienes. The 1,4-dilithio-1,3-butadienes can be accessed readily in high efficiency with a wide variety of substitution patterns on the butadienyl skeleton. The configuration has been predicted and demonstrated to favor a double dilithium bridging structure in both solution and solid states. The two Li atoms are bridged by a butadiene moiety and are in close proximity. By taking advantage of this unique configuration, we have developed useful and interesting synthetic methodologies. Three types of reactions of 1,4-dilithio-1,3-butadienes, termed dilithio reagents here, have been developed and are discussed. An intramolecular reaction is introduced in the first section. The reaction is a result of the intracooperative effect among the two C-Li moieties, the butadienyl bridge, and the substituents. A useful transformation from silylated 1,4-dilithio-1,3-butadienes to α-lithio siloles is described. Second, we discuss an intermolecular reaction that results from the intercooperative effect of the two C-Li moieties toward substrates. As an example of the formation of functionalized cyclic dianions from the linear dianions of the dilithio reagents and organic substrates, we describe the isolation and structural characterization of a novel type of cyclic dianion; that is, fully substituted oxy-cyclopentadienyl dilithium formed via the reaction of dilithio reagents with CO. We also describe diverse reactions of dilithio reagents with nitriles to form substituted pyridines, tricyclic 1-bipyrrolines, and siloles, demonstrating the remarkable effect of substituents on the butadienyl skeleton. Third, we discuss transmetalation of dilithio reagents to generate other organo-dimetallic compounds. This section focuses on organo-dicopper compounds and their reactivity toward the synthesis of strained ring systems, such as semibullvalenes and twisted four-membered rings, with the metal-mediated C-C bond-forming approach. In addition to these three representative reactions, other useful applications are also briefly introduced. The dimetallic 1,4-dilithio-1,3-butadienes and their transmetalated derivatives provide unique synthetic organometallic reagents that are very different from monometallic reagents, both in terms of reactivity and synthetic application. These organo-dimetallic reagents provide access to interesting and useful compounds that are not available by other means. Moreover, given the possibilities afforded, the study of organo-dimetallic and organo-polymetallic compounds should yield further synthet...

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Section: Intermolecular Reactionsmentioning

confidence: 99%

Section: Dilithio Reagents Rarelymentioning

confidence: 99%

1,4-Dilithio-1,3-dienes: Reaction and Synthetic Applications

2010

Acc. Chem. Res.

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124

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“…Among the huge family of 1,3-butadienes, however, the structural variation of 1,4-dihalo-1,3-butadienes is very limited, presumably because synthetic methodologies have not been widely explored although these compounds are also potentially useful in organic synthesis. Indeed, use of these compounds can be seen in the synthesis of conjugated polyenes, benzene derivatives, naphthalenes, cyclopentadiene derivatives, pyridines, furans, thiophenes, pyrrole, siloles and other group 14 congeners, phospholes, and other pnictogen congeners …”

Section: Introductionmentioning

confidence: 99%

Synthesis of 1,4-Dichloro-1,3-butadienes by Rhodium Complex Catalyzed Reaction of Terminal Alkynes with Trichloroacetyl Chloride

et al. 2009

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Chlorinative dimerization of terminal alkynes with trichloroacetyl chloride as chlorine donor proceeds in the presence of rhodium catalysts to give (Z,Z)-1,4-dichloro-1,3-butadienes stereoselectively. Ligand screening has revealed that reactions using sterically bulky and electron-donating ligands like trimesitylphosphine are high yielding. The reaction is compatible with a range of functional groups to give the title compounds nearly quantitatively in most cases. A mechanistic possibility involving coupling of beta-chloroalken-1-yl intermediate has been discussed.

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“…Compared to the Tamao-Yamaguchi method for the preparation of lithio siloles, this route is more general in terms of substitution patterns and versatility [58][59][60][61]. Stable enols were successfully synthesized from similar 1,4-dilithio-1,3-dienes and a novel de-aromatization/Michael addition/ re-aromatization domino process was believed to be involved in the reaction [62].…”

Section: 4 14-bimetallic Compoundsmentioning

confidence: 99%

Recent developments in homobimetallic reagents and catalysts for organic synthesis

Shimeng

et al. 2011

Chin. Sci. Bull.

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Organometallics are a family of useful organic chemicals because they play important roles in organic synthesis as reagents and as catalysts. They can be classified according to the number of metals they contain. Bimetallic compounds are important organometallics and they are either homobimetallic or heterobimetallic depending on whether the two metals are the same or different. In this paper, we focus on homobimetallic compounds. Homobimetallic compounds are generally used as dianions to react with electrophiles in organic synthesis. Recently, homobimetallics have also been used as catalysts in organic reactions such as in asymmetric reactions. homobimetallics, reagent, catalyst, synthesis, application Citation:Wu W, Gu D L, Wang S M, et al. Recent developments in homobimetallic reagents and catalysts for organic synthesis.

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Formation of stable enols from 1,4-dilithio-1,3-dienes and acid chlorides by a de-aromatization/Michael addition/re-aromatization domino process

Abstract: Stable enols were synthesized from the reaction of (1Z,3Z)-1,4-dilithio-1,3-dienes with acid chlorides and structurally characterized by single-crystal X-ray analysis. These stable enols were formed by a novel de-aromatization/Michael addition/re-aromatization domino process.

Cited by 10 publications

References 54 publications

1,4-Dilithio-1,3-dienes: Reaction and Synthetic Applications

1,4-Dilithio-1,3-dienes: Reaction and Synthetic Applications

Synthesis of 1,4-Dichloro-1,3-butadienes by Rhodium Complex Catalyzed Reaction of Terminal Alkynes with Trichloroacetyl Chloride

Recent developments in homobimetallic reagents and catalysts for organic synthesis

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