Carbon network building blocks: triethynyl methanol and derivatives

Alberts, Albert H.; Wynberg, Hans

doi:10.1039/c39880000748

Cited by 36 publications

(17 citation statements)

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“…In 1988, Alberts and Wynberg reported the isolation of a trimethylsilyl‐protected 1,1,3‐triethynylallene 18. However, despite intensive synthetic efforts over the past 20 years, neither 1 nor any substituted derivative has ever been isolated 19.…”

Section: 1 Development Of Ethynylallene Building Blocksmentioning

confidence: 99%

Allenes in Molecular Materials

2012

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This Minireview provides a critical account of the development of allene-containing advanced functional materials, starting with the design and synthesis of stable and enantiopure building blocks. A variety of systems, including shape-persistent macrocycles, foldamers, polymers, charge-transfer chromophores, dendrimers, liquid crystals, and redox-switchable chiral chromophores are discussed from the viewpoint of their syntheses, properties, and potential applications. The goal of this Minireview is to inspire new uses of enantiopure allenes for the rational design of advanced materials.

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Section: 1 Development Of Ethynylallene Building Blocksmentioning

confidence: 99%

Allenes in Molecular Materials

2012

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“…Whereas silylated derivatives of peralkynylated butatriene 4 have been reported [5], the ethynylated allenes (AE)-5 and 6 have remained elusive, despite intensive efforts aimed at their preparation [6]. During an attempted preparation of tetraethynylmethane, evidence for the formation of 1,1,3-triethynylallene in a mixture of products was obtained [7]; also, mono-alkynylated allenes are well-known [8]. The major problems encountered in previous attempts to synthesize the novel C-rich building blocks (AE)-5 and 6 were their high tendency for rearrangement and facile [2 2] cycloaddition, which occurred readily even at room temperature [6].…”

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confidence: 99%

1,3-Diethynylallenes: Carbon-Rich Modules for Three-Dimensional Acetylenic Scaffolding

Livingston

Cox

Odermatt

et al. 2002

HCA

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Dedicated to Professor Dieter Seebach on the occasion of his 65th birthday Regioselective Pd 0 -catalyzed cross-coupling of substrates, which bear bispropargylic leaving groups with silyl-protected alkynes, has provided access to a variety of 1,3-diethynylallenes, a new family of modules for three-dimensional acetylenic scaffolding. In enantiomerically pure form, these C-rich building blocks could provide access ± by oxidative oligomerization ± to a fascinating new class of helical oligomers and polymers with all-carbon backbones (Fig. 2). In the first of two routes, a bispropargylic epoxide underwent ring opening during S n 2'-type cross-coupling, and the resulting alkoxide was silyl-protected, providing 1,3-diethynylallenes (AE)-8, (AE)-12 (Scheme 3), and (AE)-15 (Scheme 5). A more general approach involved bispropargylic carbonates or esters as substrates (Scheme 6 ± 8), and this route was applied to the preparation of a series of 1,3-diethynylallenes to investigate how their overall stability against undesirable [2 2] cycloaddition is affected by the nature of the substituents at the allene moiety. The investigation showed that the 1,3-diethynylallene chromophore is stable against [2 2] cycloaddition only when protected by steric bulk and when additional pelectron delocalization is avoided. The regioselectivity of the cross-coupling to the bispropargylic substrates is entirely controlled by steric factors: attack occurs at the alkyne moiety bearing the smaller substituent (Schemes 9 and 10). Oxidative Hay coupling of the terminally mono-deprotected 1,3-diethynylallene (AE)-49 afforded the first dimer 50, probably as a mixture of two diastereoisomers (Scheme 12). Attempts to prepare a silyl-protected tetraethynylallene by the new methodology failed (Scheme 13). Control experiments (Schemes 14 ± 16) showed that the Pd 0 -catalyzed cross-coupling to butadiyne moieties in the synthesis of this still-elusive chromophore requires forcing conditions under which rapid [2 2] cycloaddition of the initial product cannot be avoided.

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“…Expansion of the central olefinic fragment in DEEs and TEEs leads to the di‐ and tetraethynylated allenes (±)‐ 3 and 4 , and butatrienes 5 and 6 (Scheme ). Whereas silylated derivatives of peralkynylated butatriene 6 have been reported,7 1,3‐diethynyl‐ and tetraethynylallenes have remained elusive, despite intensive efforts aimed at their preparation 8. The major problems encountered in previous attempts to synthesize these novel building blocks for three‐dimensional acetylenic scaffolding were their high tendency for rearrangement and facile [2+2] cycloaddition, which occurred readily even at room temperature or below 9…”

Section: Methodsmentioning

confidence: 99%