81396-16-9

Upstream product

• 81396-19-2 5-Phenyl-3a,9b-dihydro-3H-cyclopenta[a]naphthalene 
• 81396-15-8 7,7-Diphenyl-bicyclo[3.2.0]hept-2-en-6-ol 
• 945546-82-7 5-hydroxy-5-phenyl-1,2,3,5-tetrahydrocyclopenta[a]naphthalene-9b-carboxylic acid tert-butyl ester 
• 22524-25-0 1-phenylhex-5-en-1-one 
• 100-52-7 benzaldehyde 

Relevant academic research and scientific papers

Aromaticity-Driven Access to Cycloalkyl-Fused Naphthalenes

We report the efficient synthesis of cycloalkyl-fused naphthalenes through the [4 + 2]-cycloaddtion/decarboxylative aromatization of alkyne-tethered aryne insertion adducts. These scaffolds were difficult to synthesize using conventional reactions. The reaction proceeds via the formation of a benzopyrylium intermediate followed by intramolecular [4 + 2] cycloaddition and a subsequent decarboxylation pathway. This method is also compatible with allene-tethered substrates to afford similar products. In addition, the one-pot synthesis of polysubstituted naphthalenes via aryne insertion/benzannulation has also been developed in good yield.

Formal radical closure onto aromatic rings-a general route to carbocycles

A general method is described for indirectly effecting radical carbocyclization of an alkyl chain onto an aromatic ring. Birch reductive-alkylation of aromatic tert-butyl esters with α,ω- dibromides, chromium(vi)-mediated oxidation of the resulting 1,4-dienes and Finkelstein displacement of Br- with NaI gives cross-conjugated ketones that undergo radical cyclization. The products are easily aromatized to phenols by silylation, Saegusa oxidation and treatment with BiCl 3.H2O. A special feature of the route is that it allows attachment of a substituent to the original aromatic ring in place of the phenolic oxygen of the normal product.

Formation of benzo-fused carbocycles by formal radical cyclization onto an aromatic ring

Equation Presented An indirect method for effecting radical carbocyclization onto aromatic rings is described. Cross-conjugated dienones such as 13, readily prepared by Birch reduction of aromatic fert-butyl esters, in situ alkylation, and oxidation (10 → 11 → 12 → 13), undergo radical cyclization; the products (14) are aromatized by silylation, Saegusa oxidation, and treatment with BiCl3·H2O. A noteworthy feature of this route is that it provides opportunities to attach an additional substituent to the original aromatic ring.

Rhenium-catalyzed synthesis of naphthalene derivatives via insertion of aldehydes into a C-H bond

A rhenium complex, [ReBr(CO)3(THF)]2, catalyzed reactions of aromatic ketimines and aldehydes with dienophiles, followed by dehydration, to give naphthalene derivatives in good to excellent yields. This reaction proceeds via C-H bond activation, insertion of an aldehyde, intramolecular nucleophilic cyclization, reductive elimination, elimination of aniline and Diels-Alder reaction. After dehydration, naphthalene derivatives were formed.

Rhenium-catalyzed insertion of aldehyde into a C-H bond: Synthesis of isobenzofuran derivatives

A rhenium complex, [ReBr(CO)3(thf)]2, catalyzed reactions of aromatic ketimines with aldehydes to give isobenzofuran derivatives in good to excellent yields. In contrast to ruthenium and rhodium catalysts, aldehydes, which are polar unsaturated molecules, inserted into the C-H bond after activation by the rhenium complex. Copyright

Acid-catalyzed rearrangement of cyclobutanols. Syntheses of chrysenes, cyclopentenophenanthrenes, and diarylmethanes

Acid-catalyzed reactions of 8-aryl or 8,8-diarylbicyclooct-2-en-7-ols lead to tetrahydrophenanthrene derivatives.For example 8-(1-naphthyl)-bicyclooct-2-en-7-ols give substituted chrysenes in methanesulphonic acid.In the case of the homologous 7-aryl or 7,7-diarylbicyclohept-2-en-6-ols a novel transformation of diarylmethanes is observed.A mechanism is proposed which accounts for the product distribution observed in these rearrangements.

A NOVEL ACID-CATALYZED REARRANGEMENT OF CYCLOBUTANOLS

Under acid-catalysis 7-arylbicyclohept-2-en-6-ols rearrange to diarylmethanes and cyclopenteno-annelated polycyclic aromatic hydrocarbons