Synthesis and Crystal Structure of 1-(4-Chlorophenyl)-2-cyano-3-amino-3a-hydroxy- 3a,3b,6,7-tetrahydrobenzo[4,5]indene

The title compound 1-（4-chlorophenyl）-2-cyano-3-amino-3a-hydroxy-3a,3b,6,7- tetrahydro-benzo[4,5]indene 2, has been synthesized by the reductive cyclization of 2-cyano-3- （4-chlorophenyl）-3-（1-tetralon-2-yl） propionitrile 1 induced by low-valent titanium reagent and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group C2/c with a = 28.244（7）, b = 14.401（3）, c = 21.245（3）A,β= 115.71（2）°, V = 7786（3）A^3, Mr= 696.13, Dc = 1.188 g/cm^3, Z = 8,μ（MoKα） = 0.208 mm^-1, F（000） = 2916, R = 0.0783 and wR = 0.2350. X-ray analysis reveals that the five-membered ring （C（7）～C（l l）） adopts an envelop conformation, while the six-membered ring （C（10）～C（14）, C（19）） has a half-chair conformation. Meanwhile, intermolecular H-bond interactions result in the formation of polymer.

Syntheses of Substituted Indan-1-onesand Indenes

The syntheses of three novel substituted indanones namely 2,7 dimethylindan 1 one, 2 methyl 4,7 diethylindan 1 one and 2,4 dimethyl 7 methoxyindan 1 one are described. These indanones were prepared by different routes involving intramolecular ring closure of aryl substituted compounds by Friedel Crafts reaction. The t butyl was used as the positional protective group in the selective preparation of 2,7 dimethylindan 1 one. The corresponding indenes were prepared by reduction and dehydration reactions from these indanones.

Reductive Coupling of Aryl Halides via C-H Activation of Indene

This paper describes the first case of a reductive coupling reaction with indene,a non-heteroatom olefin used as a reducing agent.The scope of the substrate is wide.The homo-coupling,cross-coupling,and synthesis of 12 and 14-membered rings were realized.The control experiment,indene-product curve and density functional theory calculations showed that the η^(3)-palladium indene intermediate was formed by C-H activation in the presence of cesium carbonate.We speculate that the final product was obtained through a Pd(IV)intermediate or aryl ligand exchange.In addition,we excluded the formation of palladium anion(Pd(0)^(-))intermediates.

Gold-catalyzed ketene dual functionalization and mechanistic insights:divergent synthesis of indenes and benzo[d]oxepines

An unprecedented gold-catalyzed ketene C=O/C=C bifunctionalization method has been developed.Mechanistic studies and density function theory(DFT)calculations indicate that the reaction is initiated by gold-catalyzed Wolff rearrangement of diazoketone to form the ketene intermediate,followed by intermolecular nucleophilic addition and terminated with two divergent cyclization processes via enol intermediates.In the case with alcohols as the nucleophiles,the reaction goes through a C-5-endodig carbocyclization to give the indene products;whereas,O-7-endo-dig cyclization occurs dominantly when indoles/pyrroles are used as the nucleophiles,delivering the 7-membered benzo[d]oxepines.In comparison with the well-documented cycloaddition and nucleophilic addition reactions,this cascade reaction features a novel reaction pattern for the ketene dual functionalization through addition with nucleophile and electrophile in sequence.

Metal-Free Arylsulfonyl Radical Triggered Cascade Cyclization of Phenyl-Linked 1,6-Enynes:Synthesis of 2,3-Dihydro-1H-indenes and 10a,11-Dihydro-10H-benzo[b]fluorines

Aryl sulfonyl radical triggered cascade cyclization of phenyl-linked 1,6-enynes for the synthesis of biologically important indenes containing alkenyl C—X bonds and 10a,11-dihydro-10H-benzo[b]fluorines is presented.In these radical cascade processes,three new chemical bonds,including C—S,C—C,and C—X bonds,and three C—C bonds are formed in one step.The method is attractive and valuable due to its metal-free,mild reaction conditions,broad substrate scope and good functional group tolerance.

TfOH/Fe（OTf）3 Cocatalyzed Reaction of Arylallenes with Alcohols for Structurally Diverse Indene Derivatives

The indene moiety is an important unit because of its presence in many chemical catalysts, functional materials and biologically relevant molecules. Herein, we report a facile reaction of arylallenes with benzylic or allylic alcohols through TfOH/Fe（OTf）3 cocatalyzed cleavage of sp3 carbon-oxygen. In the presence of 5 mol% TfOH and 5 mol% Fe（OTf）3, a range of arylallenes undergo carbocation initiated cyclization reaction with alkyl alcohols to give structurally diverse polysubstituted indenes in good to excellent yields. H2O is the sole byproduct that makes this transformation highly atom-economic and environmentally benign.

Crystal Structure of Indenyl-3-indenyl

The crystal structure of the title compound (C18H16, Mr = 232.31) has been determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 6.3449(9), b = 6.6297(9), c = 15.727(2) ? ?= 94.338(3), ?= 0.71073 ? ?= 0.066 mm-1, V = 659.66(16) 3, Z = 2, Dc = 1.170 g/cm3 and F(000) = 248. The structure was refined to R = 0.0560 and wR = 0.1426 for 771 observed reflections with I > 2(I). X-ray diffraction analysis reveals that the title compound is a dimer of indene.

Mechanistic Studies on Propargyl Alcohol-Tethered Alkylidenecyclopropane with Aryldiazonium Salt Initiated by Visible Light

This paper discloses the reaction mechanism of two consecutive but different visible light photo-induced chain processes for the rapid construction of spirobi[indene]skeletons.The first process is triggered by a photo-induced single-electron-transfer(SET)of an electron donor-accepter(EDA)complex.The second process is initiated by a direct SET process between aryldiazonium salt and the excited allenic intermediate.In these two processes,another SET took place respectively on the in situ formed radical intermediate to realize a redox-neutral outcome.The mechanistic studies have been carried out by control experiments,kinetic and spectroscopic analyses,deuterium labeling experiments to support these two chain processes.