187-83-7

Usage

Uses

Used in Asymmetric Polymerization:
(6)HELICENE is used as a C2-chiral catalyst in the asymmetric polymerization of triphenylmethyl methacrylate. Its unique helical structure allows for the selective catalysis of specific reactions, leading to the production of polymers with desired chiral properties. This application is particularly relevant in the field of materials science and polymer chemistry, where the development of novel materials with specific characteristics is of great interest.

InChI:InChI=1/C26H16/c1-3-7-22-17(5-1)9-11-19-13-15-21-16-14-20-12-10-18-6-2-4-8-23(18)25(20)26(21)24(19)22/h1-16H

Upstream product

• 20508-11-6 (Z)-1-Phenyl-2-(2-benzophenanthrenyl)ethylene 
• 20508-12-7 (E)-1-Phenyl-2-(2-benzophenanthrenyl)ethylene 
• 32829-04-2 2-styrylbenzo[c]phenanthrene 
• 53034-15-4 2-bromobenzophenanthrene 
• 32057-88-8 2,7-distyrylnaphthalene 
• 51044-13-4 4-bromobenzyl triphenylphosphonium bromide 
• 53034-14-3 (E)-1-(4-bromophenyl)-2-(2-naphthyl)ethylene 
• 187-83-7 [6]helicene 
• 1640-39-7 2,3,3-trimethylindoleniune 
• 50874-31-2 (R)-<<(tetranitrofluorenylidene)amino>oxy>propionic acid 
• 81701-08-8 2,7-distyrylnaphthalene 
• 2418-52-2 D-threitol 
• 1730-04-7 1,8-diiodonaphthalene 
• 457885-36-8 triisopropyl{(3Z)-4-[2-({2-[(1Z)-4-(triisopropylsilyl)-1-buten-3-ynyl]-1-naphthyl}ethynyl)phenyl]-3-buten-1-ynyl}silane 

Downstream Products

• 68670-26-8 5-Acetylhexahelicen 
• 68670-27-9 8-Acetylhexahelicen 
• 77930-65-5 hexahelicene-5,6-quinone 
• 187-83-7 <6>-helicene 
• 187-83-7 <6>-helicene 
• 68858-28-6 5-aminohexahelicene 
• 187-83-7 phenanthro[3,4c]phenanthrene 
• 68670-20-2 5,6,11,12-Tetrabromo-5,6,11,12-tetrahydrohexahelicen 
• 68670-23-5 5-Nitrohexahelicen 
• 68670-24-6 8-Nitrohexahelicen 
• 68670-22-4 5,12-Dibromohexahelicen 
• 68670-21-3 5-Bromohexahelicen 

Relevant academic research and scientific papers

Helicene synthesis by Br?nsted acid-catalyzed cycloaromatization in HFIP [(CF3)2CHOH]

A facile synthesis of carbo- and heterohelicenes was achieved via tandem cycloaromatization of bisacetal precursors, which were readily prepared through C-C bond formation by Suzuki-Miyaura coupling. This cyclization was efficiently realized by a catalytic amount of trifluoromethanesulfonic acid (TfOH) in a cation-stabilizing solvent, 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP), which readily allowed gram-scale syntheses of higher-order helicenes, double helical helicenes, and heterohelicenes.

Enantioselective Pallada-Electrocatalyzed C?H Activation by Transient Directing Groups: Expedient Access to Helicenes

Asymmetric pallada-electrocatalyzed C?H olefinations were achieved through the synergistic cooperation with transient directing groups. The electrochemical, atroposelective C?H activations were realized with high position-, diastereo-, and enantio-control

Enantioseparation on Riboflavin Derivatives Chemically Bonded to Silica Gel as Chiral Stationary Phases for HPLC

Acetylated and/or 3,5-dimethylphenylcarbamated riboflavins were prepared and the resulting riboflavin derivatives as well as natural riboflavin were regioselectively immobilized on silica gel through chemical bonding at the 5'-O- or 3-N-position of the riboflavin to develop novel chiral stationary phases (CSPs) for enantioseparation by high-performance liquid chromatography (HPLC). The chiral recognition abilities of the obtained CSPs were significantly dependent on the structures of the riboflavin derivatives, the position of the chemical bonding on the silica gel, and the structures of the racemic compounds. The CSPs bonded at the 5'-O-position on the silica gel tended to well separate helicene derivatives, while the CSPs bonded at the 3-N-position composed of acetylated and 3,5-dimethylphenylcarbamated riboflavins showed a better resolving ability toward helicene derivatives and bulky aromatic racemic alcohols, respectively, and some of them were completely separated into the enantiomers. The observed difference in the chiral recognition abilities of these riboflavin-based CSPs is discussed based on the difference in their structures, including the substituents of riboflavin and the positions immobilized on the silica gel. Chirality 27:507-517, 2015.

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

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. ARKAT-USA, Inc.

Synthesis of derivatives of phenanthrene and helicene by improved procedures of photocyclization of stilbenes

An improved method has been developed for photocyclization of stilbene to construct phenanthrenes and benzo[c]phenanthrenes. This reaction is promoted by iodine while tetrahydrofuran is used as an efficient and inexpensive scavenger of hydroiodic acid produced during the photocyclization sequence. In another process, cyclohexene is used as a reagent for dehydrogenation step in place of THFI2.

Preparation of helicenes through olefin metathesis

(Chemical Equation Presented) Metathesis with a twist! A ring-closing-metathesis strategy has been developed for the preparation of various substituted [5]helicene motifs and [6]- and [7]helicenes. The two optimized protocols include one method that utilizes the Grubbs second-generation catalyst under microwave-irradiation conditions and another that employs a modified Grubbs-Hoveyda catalyst at 40°C in a sealed reaction vessel. (Mes = mesityl).

Synthesis of [5]-, [6]-, and [7]helicene via Ni(0)- or Co(I)-catalyzed isomerization of aromatic cis,cis-dienetriynes

An original approach to helicene frameworks exploiting atom economic isomerization of appropriate energy-rich aromatic cis,cis-dienetriynes has been developed. The new paradigm provides nonphotochemical syntheses of helicenes based on the easy, convergent, and modular assembly of key cis,cis-dienetriynes and their nickel(0)-catalyzed [2+2+2] cycloisomerization. The potential of the methodology is underlined by the syntheses of the parent [5]helicene (2), 7,8-dibutyl[5]helicene (23), [6]helicene (24), and [7]helicene (25). The approach can be adapted to prepare functionalized helicenes as exemplified by the eight-step synthesis of 7,8-dibutyl-2,3-dimethoxy[6]helicene (34). Density functional theory (DFT) calculations showed that bis[2-((1Z)-1-buten-3- ynyl)phenyl]acetylene (1) and isomeric [5]helicene (2) differ enormously in the Gibbs energy content (ΔG= -136.6 kcal.mol-1) to favor highly the devised intramolecular simultaneous construction of three aromatic rings.

A new efficient access to glycono-1,4-lactones by oxidation of unprotected itols by catalytic hydrogen transfer with RhH(PPh3)4-benzalacetone system

Treatment of unprotected pentitols and hexitols with RhH(PPh3)4-benzalacetone system leads exclusively to glycono-1,4-lactones in 60-96% yield.

The influence of the chiral environment in the photosynthesis of enantiomerically enriched hexahelicene

The enrichment of one of the enantiomers (P or M) of hexahelicene (3) synthesized by the photochemical cyclodehydrogenation of 2-styryl-benzophenanthrene (1) in chiral media has been (re)investigated.Four different chiral solvents, two cholesteric liquid crystals, two chiral crystals, all at several temperatures, and two chiral polymers were used as media.To avoid erroneous values from circular-dichroism (CD) measurements due to contributions of chiral side-products, the enantiomeric excess (ee) was determined by HPLC analysis.In general the observed ee is small ( 7percent).In chiral solvents the ee increases with decreasing temperatures.In the liquid crystals the macroscopic helix of the cholesteric phase has a small but distinct effect on the ee, probably due to the preferred fitting of one enantiomer of Z-1 to the helix of the 'solvent'.In chiral crystals the ee is relatively larger.A peculiar effect is observed when 1 is irradiated in ethyl (S)-(+)-O-(4-phenylbenzoyl)lactate.Below -19 deg C the M enantiomer and above -14 deg C the P enantiomer of 3 is the preferred photoproduct.In the polymer triacetylcellulose, M-hexahelicene is formed in 4.5percent excess; in β-cyclodextrine only a very small amount of 3 is formed, due to the preferred photo-isomerization into E-1.

Formation of 5,6- and 7,8-Dihydrohexahelicene: Mechanistic Details of the Rearrangement of the Primary Photocyclization Product of 2-Styrylbenzophenanthrene in the Presence of a Base

Irradiation of 2-styrylbenzophenanthrene (1) in alkylamines or basic alcoholic solution results in the formation of a mixture of two dihydrohexahelicenes (5,6- and 7,8-dihydrohexahelicene, 5 and 6).The ratio of 5 and 6 depends on the kind of solvent.In alkylamine 6 is the favored dihydrohexahelicene.In basic alcoholic solution 5 is the preferred product.Deuteration of the solvent causes a change in the ratio of 5 and 6 in favor of 5.The reaction starts with the deprotonation of the primary formed, unstable 16d,16e-dihydrohexahelicene (2), followed by a protonation step.The site of this protonation determines the ratio of 5 and 6 and depends upon the acidity of the protonating agent, an alkylammonium cation or solvent molecule, and the electron densities at the various possible sites for protonation in the intermediate.Irradiation of 1 in several chiral alkylamines yielded optically enriched 6.