Syntheses and Crystal Structures of Two Novel Spiro Compounds Containing 1,5-Dioxaspiro[5.5]undecane-2,4-dione

Two novel spiro compounds,3-benzylidene-1,5-dioxaspiro[5.5]undecane-2,4-dione 1 and 3-（2-fluorobenzylidene）-1,5-dioxaspiro[5.5]undecane-2,4-dione 2,have been synthesized and characterized by X-ray single-crystal diffraction,IR and elemental analysis.Compound 1 belongs to the monoclinic system,space group P21/n with a=12.326（3）,b=5.6420（11）,c=20.089（4）,β= 101.79（3）o,C16H16O4,Mr= 272.29,V=1367.7（5）3,Z=4,Dc=1.322g/cm3,F（000）=576,μ（MoKa）=0.095 mm-1,the final R=0.0420 and wR=0.1159.Compound 2 is of monoclinic system,space group P21/n with a=12.283（3）,b=5.6367（11）,c=20.055（4）,β=102.00（3）o,C16H15FO4,Mr=290.28,V=1358.2（5）3,Z=4,Dc=1.420 g/cm3,F（000）=608,μ（MoKa）=0.110 mm-1,the final R=0.0353 and wR=0.0860.

DNA Modification with Photochromic Spiro Compounds

The photochromic spiropyrans and spirooxazine having a succinimidyl ester or isothiocyanate pendant group can form covalent products with transaminated DNA. The absorption spectra and solid reflection spectra of modified DNA with these photochromic spiro compounds were investigated.

Synthesis and Structure Elucidation of New Spiro Compounds with Per（poly）fluoroalkyl Group

A series of spiro compounds have been synthesized via several steps. The structure of these compounds were confirmed by ^1H NMR, 13C NMR, IR, MS spectra and X-ray diffraction analysis. The possible mechanism to form these products was also proposed.

Photo‐catalyzed sequential dearomatization/carboxylation of benzyl o‐halogenated aryl ether with CO_(2) leading to spirocyclic carboxylic acids

Photo‐catalyzed tandem dearomatization/carboxylation of benzyl o‐halogenated aryl ether with CO_(2) was achieved,which affords spirocyclic carboxylic acids under mild conditions.The reaction has good functional group tolerance with high yields.Mechanism studies indicate that the transformation was realized via intramolecular radical addition and nucleophilic addition.

Copper-Initiated Radical Dearomative 2,5-Alkylarylation of Furans via Trihalomethylation/Spirocyclization Cascade

Here is an operable and rare strategy for copper-initiated radical dearomative 2,5-alkylarylation of furan. By means of this strategy, we realized the dearomatization of furans to construct spirooxindoles with good yield in one-step via trihalomethylation/spirocyclization cascade progress.

Making Spiroketal-based Diphosphine （SKP） Ligands via a Catalytic Asymmetric Approach

The spiro concept for chiral ligand design represents an important contribution to the area of asymmetric catalysis. Due to the considerable difficulties in the construction of enantiopure all-carbon spiro backbones, the development of catalytic asymmetric synthesis of chiral spiro structures via short steps is highly valuable. Herein we present our studies on the catalytic asymmetric synthesis of aromatic spiroketals and the corresponding diphos- phine （SKP） ligands.

[bmim]OH： An efficient catalyst for the synthesis of mono and bis spirooxindole derivatives in ethanol at room temperature

A rapid and efficient, one pot synthesis of spirooxindole derivatives has been attempted by three- component reaction of isatin, malononitrile and carbonyl compound possessing a reactive c^-methylene group by using task specific ionic liquid, 1-butyl-3-methyl imidazolium hydroxide [bmim]OH as a catalyst. The important features of this methodology are straight forward route in short reaction time at room temperature and avoid any hazardous organic solvent, toxic catalyst, tedious purification step. Interestingly, this protocol is not only limited to mono-systems but also to the synthesis of newer bis- spirooxindole system. The separation of the product and reusability of the catalyst are easy with excellent yield. The [bmim]OH catalyst system could be reused up to five recycles without appreciable loss of activity.

An Efficient Four-component Synthesis of Spiro[indolinepyrazolo[4＇,3＇：5,6] pyrido[2,3-d] pyrimidine]triones

A four-component reaction in the presence of Alum [KAl（SO4）2·12H2O] as an inexpensive and reusable catalyst using the ionic liquid as an effective green reaction media is reported.

Synthesis of a 1,2,7,8-Tetraoxa-spiro[5.5]undecane

Synthesis of a new spiro organic peroxide is described. The peroxy bonds were incorporated into the substrate framework via an acid-catalyzed ketal exchange reaction using hydrogen peroxide as the source of peroxy linkage. The hydroperoxyl groups were then bonded at the OH ends via Hg（II）-induced electrophilic additions to the C-C double bonds, giving a novel sprio structure with one peroxy bond in each of the two six-membered rings. The ester functionalities in the side chains also make it possible to conduct further structural modifications.

Efficient Synthesis of the Functionalized Spiro[indoline-3,4＇-pyridine] via Four-component Reaction

An efficient synthetic procedure for the functionalized spiro[indoline-3,4＇-pyridine] was developed via the four-component reactions of arylamines, acetylenedicarboxylates, isatins and malononitrile with triethylamine as the base catalyst. The advantages of this reaction are using common starting material, mild reaction conditions, broad scope of reactants and operational simplicity.

Efficient Synthesis of Spiro[furan-3,3＇-indoline] Derivatives via Reactions of Pyridinium Salts with Isatinylidene Acetoacetates

An efficient synthetic procedure for the functionalized spiro[furan-3,3＇-indoline] derivatives was successfully developed by domino reactions of N-phenacylpyridinium bromides or N-ethoxycarbonylmethylenepyridinium bro- mide with isatinylidene acetoacetate in the presence of triethylamine in ethanol at room temperature. The mecha- nism included sequential Michael addition of the in situ generated pyridinium ylide and intramolecular substitution of enolate.

Convenient Synthesis of Spiro[benzo[d]pyrrolo[2,1-b]thiazole- 3,2＇-indenes] Derivatives via Three-Component Reaction

The three-component reaction of N-phenacylbenzothiazolium bromides, aromatic aldehydes and indane-l,3- dione in ethanol at room temperature in the presence of triethylamine as base afforded functionalized spiro[benzo- [d]pyrrolo[2,1-b]thiazole-3,2＇-indenes] in good yields and with high diastereoselectivity. The 1H NMR data and sin- gle crystal structure clearly indicated that the obtained spiro compounds predominately have one diastereoisomer.

Theoretical Studies on Aromaticity of Spiro Metallaaromatics of （CloH10M）^2-（M=Ni, Pd, Pt）

Aiming to identify the spiro metallaaromatic systems with potential application value, （C10H10M）2 （M=Ni, Pd, Pt） derivatives were theoretically investigated. （C10H10M）^2 -Isol, which has two 6-membered rings（6MRs） connected by the M spiro atom, is a 14π-aromatic as a whole plane. （CloH10M）2 -Iso2 has one 6π-aromatic 5MR and one 10π-aromatic 7MR connected by the spiro atom. The free （C10H10M）^2- dianions could not exist due to their rather high frontier orbital energies, while the neutral （C10H10M）Li2 compounds are extremely stable against dissociation. Since （C10H10M）Liz coumponds axe not fully coordinated, they trend to form （C10H10M）Li4^2＋ dications, or even [（C10H10M）Li2]n polymers. Arguably, （C10H10M）^2- planes are not the only examples for spiro metallaaromaticity, their derivatives are also potential material building blocks.

Spiro(phosphoamidite) ligand(SIPHOS)/Cu(OTf)2-catalyzed highly regio-and stereo-selective hydroborations of internal alkynes with diborane in water

The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.

Derivation of Benzothiadiazine-1,1-dioxide Scaffolds via Transition Metal-Catalyzed C-H Activation/Annulation

Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives through transition metal-catalyzed C—H activation/annulation was reported.3-Phenyl-2H-benzothiadiazine-1,1-dioxide was used as the reaction substrate,and vinylene carbonate and 4-diazopyrazolone were used as the coupling reagents,respectively.This strategy provides straightforward access to complex N-heterocycles in a highly efficient and simple manner.

Novel Porphyrin-Containing Polymer Based Memristor for Synaptic Plasticity Simulation

The porphyrin-based copolymer PZnTPP-SFX is designed and synthesized by alternating porphyrin and spiro[fluorene-9,9'-xanthene]via Suzuki copolymerization.A simple memristor structure of ITO/ZnTPP-SFX/AlOx/Al was fabricated by spin-coating process.The conventional synaptic plasticity is emulated using the single memristor including nonlinear transmission characteristics,spike-timing dependent plasticity and spike-rate dependent plasticity.New spike-voltage dependent plasticity is also found in the memristor which can selectively perform potentiation and depression behaviors at a unipolar voltage.Compared with the device performance of uncoordinated metalloporphyrin polymer,it was found that oxygen vacancies diffuse and migrate into PZnTPP-SFX layer with the assist of coordination metal.This study suggests that porphyrin-based polymers have great promise for synaptic simulation of artificial neural network.

Molecular Diversity of Three-Component Reaction of β-Enamino Imide, Malononitrile and Cyclic α-Diketones

The base promoted three-component reaction of β-enamino imide, malononitrile and various cyclic α-diketones in acetonitrile showed interesting molecular diversity. The reactions with acenaphthylene-1,2-dione and ninhydrin afforded functionalized spiro[indene-2,4＇-pyrrolo[3,4-b]pyridines] and spiro[acenaphthylene-1,4＇-pyrrolo[3,4-b]- pyridines] in good yields. The similar reaction of phenanthrene-9,10-dione resulted in the formation of the unexpected complex phenanthro[9＇, 10＇：4,5]furo[2,3-c]pyrrolo[3,4-b]pyrroles in satisfactory yields.

Molecular diversity of triphenylphosphine promoted reaction of electron-deficient alkynes and arylidene Meldrum acid(N,N’-dimethylbarbituric acid)

The three-component reaction of triphenylphosphine,dimethyl hex-2-en-4-ynedioate and arylidene N,N’-dimethylbarbituric acids in dry methylene dichloride at room temperature afforded trans-1,3-disubstituted 7,9-diazaspiro[4.5]dec-1-enes in good yields and with high diastereoselectivity.However,the similar three-component reaction with arylidene Meldrum acids resulted in a mixtures of cis/trans-1,2-disubstituted 7,9-dioxaspiro[4.5]dec-1-enes.Additionally,the three-component reaction of triphenylphosphine,dimethyl but-2-ynedioate and arylidene Meldrum acids gave polysubstituted 5-(triphe nyl-λ~5-phosphanylidene)cyclopenta-1,3-die nes.A plausible reaction mechanism was proposed for the formation of various products with different regioselectivity and diastereoselectivity.