[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids: Transannular Delocalization in Open-Circuited Conjugated Macrocycles

Boydston, Andrew J.; Bondarenko, Lidija; Dix, Ina; Weakley, Timothy J. R.; Hopf, Henning; Haley, Michael M.

doi:10.1002/1521-3773(20010817)40:16<2986::aid-anie2986>3.0.co;2-i

Cited by 37 publications

(11 citation statements)

References 34 publications

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“…As far as functional groups are concerned, we are mostly interested in the pseudo ‐geminal diethynyl16 and divinyl derivatives of [2.2]paracyclophane, the dicarboxylic acid, the bis(phenol),17 and the diamine. Having prepared all of these during the last few years, we now describe in this paper the preparation, chemical properties, and the use of 4,15‐diamino[2.2]paracyclophane in a cyclic process like the one described, thus for the first time demonstrating the feasibility of the above principle.…”

Section: Resultsmentioning

confidence: 99%

4,15-Diamino[2.2]paracyclophane, a Reusable Template for Topochemical Reaction Control in Solution

et al. 2002

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An efficient synthesis of [2.2]paracyclophane-4,15-dicarboxylic acid (11) from [2.2]paracyclophane (8) has been developed. The diacid was converted via the diazide 14 into the 4,15-diisocyanato[2.2]paracyclophane (15), a versatile intermediate that could be transformed into many new pseudogeminally substituted derivatives of 8. For example, treatment of 15 with alcohols provided the carbamates 16 and 17. On treatment of 15 with diisopropylamine, the urea 18 was obtained, whereas reduction with lithium aluminium hydride afforded the cyclic urea 20. Hydrolysis of 15 furnished the

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Section: Resultsmentioning

confidence: 99%

4,15-Diamino[2.2]paracyclophane, a Reusable Template for Topochemical Reaction Control in Solution

et al. 2002

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“…A crude criterion for distinguishing these two fascinating classes of compounds is that a DBA has only 1,2-disubstituted aromatic units, whereas a cyclophane has at least one non-1,2-disubstituted aromatic unit. [4] Thus, the aptly named ™dehydrobenzannulene ± dimethyldihydropyrene hybrid∫ 1 reported by Haley, Mitchell, falls under the DBA category, whereas the ™[2.2]paracyclophane-dehydrobenzannulene hybrids∫ 2 and 3 described by Hopf, Haley, and coworkers [6] fall under the heading of cyclophanes. Comparison of the electronic absorption spectra of 2 and 3 with appropriate DBAs and ™broken∫ DBA analogues provided 1 2 3…”

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confidence: 99%

“Polyunsaturated” Cyclophanes

Bodwell

Satou

2002

Angewandte Chemie Intl Edit

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Cyclophane chemistry has a long and colorful history. [1] Although this discipline has evolved in many ways, several of the fundamental sources of interest in cyclophanes remain unchanged. These include the conception of novel, aesthetically pleasing and interesting structures, the challenge of synthesizing them, and the study of their properties once they have been prepared.As with other areas of synthetic chemistry, the development of new methodology has played a crucial role in the development of cyclophane chemistry. An early example of this is the emergence of the sulfur-based ring-contraction strategies that were developed in the 1960s and 1970s, [2] which paved the way for the synthesis of a very wide range of [2.2]cyclophanes and [2.2]cyclophanedienes. That these approaches are still in use today speaks to their lasting value. A more recent example is the advent of palladium-catalyzed cross-coupling reactions, [3] which opened the door for the design and synthesis of whole new families of cyclophanes, that is, those that have multiply unsaturated bridges. A selection of such ™polyunsaturated∫ cyclophanes is presented in Scheme 1.When considering compounds that are composed of aromatic units linked by unsaturated bridges, the distinction between a cyclophane and a dehydrobenzannulene (DBA) can become blurred, or even disappear entirely. A crude criterion for distinguishing these two fascinating classes of compounds is that a DBA has only 1,2-disubstituted aromatic units, whereas a cyclophane has at least one non-1,2-disubstituted aromatic unit. [4] Thus, the aptly named ™dehydrobenzannulene ± dimethyldihydropyrene hybrid∫ 1 reported by Haley, Mitchell, falls under the DBA category, whereas the ™[2.2]paracyclophane-dehydrobenzannulene hybrids∫ 2 and 3 described by Hopf, Haley, and coworkers [6] fall under the heading of cyclophanes. Comparison of the electronic absorption spectra of 2 and 3 with appropriate DBAs and ™broken∫ DBA analogues provided 1 2 3Scheme 1. Some examples of cyclophanes with multiply unsaturated bridges, made by using palladium-catalyzed cross-coupling.

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“…Since the first discovery and subsequent synthesis of [2.2]paracyclophane in the middle of the 20th century 1,2 , covalently linked π-stacked dimers have attracted intense research interest, ranging from developing new building blocks and synthetic strategies to investigating chemical consequences of their geometries and through-space electronic couplings between π-conjugated moieties 3–6 . Among these research focuses, the chemical reactivity arising from molecular geometries is of significant interest to generate novel functional properties.…”

Section: Introductionmentioning

confidence: 99%

Unveiling how intramolecular stacking modes of covalently linked dimers dictate photoswitching properties

Yan

Zhu

et al. 2019

Nat Commun

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Covalently linked π-stacked dimers represent the most significant platform for elucidating the relationship between molecular alignments and their properties. Here, we present the one-pot synthesis of two intramolecularly π-stacked dimers and disclose how intramolecular stacking modes dictate photoswitching properties. The dimer, which features cofacially stacked chromophores and geometrically favours intramolecular photochemical [2 + 2] cycloadditions, displays a nearly irreversible photoswitching behaviour. By contrast, the dimer, bearing crosswise stacked chromophores, is geometrically unfavourable for the cycloaddition and exhibits a highly reversible photoswitching process, in which the homolysis and reformation of carbon−carbon single bonds are involved. Moreover, the chiral carbon centres of both dimers endow these photoswitches with chirality and the separated enantiomers exhibit tuneable chiroptical properties by photoswitching. This work reveals that intramolecular stacking modes significantly influence the photochemical properties of π-stacked dimers and offers a design strategy toward chiral photoswitchable materials.

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[2.2]Paracyclophane/Dehydrobenzoannulene Hybrids: Transannular Delocalization in Open-Circuited Conjugated Macrocycles

Cited by 37 publications

References 34 publications

4,15-Diamino[2.2]paracyclophane, a Reusable Template for Topochemical Reaction Control in Solution

4,15-Diamino[2.2]paracyclophane, a Reusable Template for Topochemical Reaction Control in Solution

“Polyunsaturated” Cyclophanes

Unveiling how intramolecular stacking modes of covalently linked dimers dictate photoswitching properties

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