Utilisation de la Synthèse Atrolactique Pour L'Évaluation de L'Efficacité D'Inducteurs de Synthèse Asymétrique

Hassine, Béchir Ben; Gorsane, Mohamed; Geerts-Evrard, F.; Pecher, Jacques; Martin, R. H.; Castelet, D.

doi:10.1002/bscb.19860950705

Cited by 52 publications

(54 citation statements)

References 36 publications

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“…Helical arrangements and the associated chirality have well‐known implications in a variety of areas ranging from natural biological systems to materials science. In particular ortho ‐fused polyaromatic systems with π‐conjugated helical structures display unique physicochemical properties which have stimulated countless studies1 oriented towards self‐assembly and chiral recognition,2 chiroptical devices,3 molecular machines,4 material chemistry,5 organometallic and organocatalysis,6, 7 as well as asymmetric synthesis 8. 9…”

Section: Methodsmentioning

confidence: 99%

1H‐Phosphindoles as Structural Units in the Synthesis of Chiral Helicenes

et al. 2012

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Helical arrangements and the associated chirality have wellknown implications in a variety of areas ranging from natural biological systems to materials science. In particular orthofused polyaromatic systems with p-conjugated helical structures display unique physicochemical properties which have stimulated countless studies [1] oriented towards self-assembly and chiral recognition, [2] chiroptical devices, [3] molecular machines, [4] material chemistry, [5] organometallic and organocatalysis, [6, 7] as well as asymmetric synthesis. [8, 9] In the general context of the growing interest in helical derivatives, helicenes displaying phosphorus functions represent promising scaffolds. Trivalent phosphorus functions and the related metal complexes are easily designed to tune the electronic and physicochemical properties of helicenes, [10] as well as to offer a wide range of potential uses in organometallic chemistry and catalysis. It is therefore rather surprising to note that the field today is still in its infancy, first of all in terms of number of compounds as well as structural diversity. So far, most phosphorus derivatives having helical chirality display polyaromatic (or heteroaromatic) helical scaffolds with pendant phosphorus functions (phosphites, [2a, 6b, 11] trivalent phosphines and phosphine oxides, [6a, 12] phospholes, [10a,b] etc.). Very little is known about their properties and behaviors.The aim of this work is to expand the range of heterohelicenes to chiral helicenes where phosphorus is embedded within the helical framework itself, at the external edge of the fused ring sequence (Figure 1). Helical phosphines of this class would not only display peculiar electronic features resulting from extended p conjugation, but also take full advantage of the dissymmetric steric environment generated by the helical chirality at the external edge. Helicenes of this class are unknown to date, whereas phosphahelicenes, wherein phosphorus is embedded in the internal section of the helical framework, have been reported only recently by Tanaka and co-workers and Nozaki and co-workers. [13] We intend to disclose here: a) the first diastereo-and enantioselective access to [6]-and [7]helicenes in which the fused ring sequence ends with a phosphole unit; b) the structural and chiroptical properties of enantiomerically pure derivatives of this class; c) the enantiospecific self-assembly of columnar arrangements in the solid state; and d) the photochemical [2+2] annulations of phosphole-fused [6]helicenes into dimeric helical structures.When targeting helicenes where phosphorus is embedded within the helical framework itself, we envisioned 1Hphosphindole oxides as suitable building blocks and have adapted the classical helicene synthesis, based on the photochemical cyclization/dehydrogenation of diarylolefins, to these substrates. [14] Our starting materials are the olefins 5 which combine a 1H-phosphindole unit and a benzo[c]phenanthrene fragment. They have been prepared according to a known procedure, [15] by usi...

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Section: Methodsmentioning

confidence: 99%

1H‐Phosphindoles as Structural Units in the Synthesis of Chiral Helicenes

et al. 2012

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“…In the mid 1980's, several types of diastereoselective reactions involving carbohelicenes were presented, for instance, an early report on hydroxyamination of an alkene. 4 In Scheme 1, a highly diastereoselective reduction with NaBH 4 of a ketone function from a a-ketoester derived from (rac) 2-hydroxy- [7]helicene was achieved (99% yield; 99% d.e.). 5 When other alcohol auxiliaries (rather than 2-hydroxy- [7]helicene) were used in the ester part of the a-ketoester, the d.e.…”

Section: Helicenes In Diastereoselective Stoichiometric Reactionsmentioning

confidence: 99%

“…4 In Scheme 1, a highly diastereoselective reduction with NaBH 4 of a ketone function from a a-ketoester derived from (rac) 2-hydroxy- [7]helicene was achieved (99% yield; 99% d.e.). 5 When other alcohol auxiliaries (rather than 2-hydroxy- [7]helicene) were used in the ester part of the a-ketoester, the d.e. was lower.…”

Section: Helicenes In Diastereoselective Stoichiometric Reactionsmentioning

confidence: 99%

One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

2013

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Carbohelicenes are a class of fascinating chiral helical molecules which have a rich history in chemistry. Over a period of almost 100 years, chemists have developed many methods to prepare them in a racemic or in a non-racemic form. They also possess a series of interesting chiral, physical, electronic and optical properties. However, their utilization in chemistry or chemistry-related fields has rarely appeared in a detailed and comprehensive review. It is the purpose of this review to collect fundamental applications and functions involving carbohelicenes in various disciplines such as in materials science, in nanoscience, in biological chemistry and in supramolecular chemistry. From the numerous synthetic methodologies reported up to now, carbohelicenes and their derivatives can be tailor-made for a better involvement in several subfields. Among those domains are: nanosciences, chemosensing, liquid crystals, molecular switches, polymers, foldamers, supramolecular materials, molecular recognition, conductive and opto-electronic materials, nonlinear optics, chirality studies and asymmetric synthesis. Helicene chemistry is now at a developmental stage, where sufficient application data are now collected and are extremely useful. They provide many more ideas for setting up the basis for future innovative applications.

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“…6 Study of helical compounds is an active field of research in supramolecular chemistry due to their self-assembly and physiochemical properties. 7 Also their rigid helical framework, high optical stability and unique chiral array can provide functionalized helicenes such as alcohols, 8 nitriles, 9 amines 10 and phosphines 11 for use as chiral catalysts, 12 ligands 13 and auxiliaries in asymmetric synthesis. Moreover helicenes possessing inherent chirality have attracted attention owing to their extraordinary electronic and optical properties.…”

Section: Introductionmentioning

confidence: 99%

Expeditious synthesis of helicenes using an improved protocol of photocyclodehydrogenation of stilbenes

Talele¹,

Chaudhary²,

Patel³

et al. 2011

Arkivoc

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An improved procedure has been developed for photodehydrocyclization of stilbenes for the synthesis of phenanthrenes and helicenes. This procedure involves the use of THF as a scavenger of hydriodic acid produced during iodine mediated photodehydrocyclization. The use of THF is advantageous due to its higher boiling point, lower cost and easy availability as compared to propylene oxide. The method is applied to synthesize a number of phenanthrenes and helicenes.

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Utilisation de la Synthèse Atrolactique Pour L'Évaluation de L'Efficacité D'Inducteurs de Synthèse Asymétrique

Cited by 52 publications

References 36 publications

1H‐Phosphindoles as Structural Units in the Synthesis of Chiral Helicenes

1H‐Phosphindoles as Structural Units in the Synthesis of Chiral Helicenes

One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

Expeditious synthesis of helicenes using an improved protocol of photocyclodehydrogenation of stilbenes

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