Synthesis and Solid‐State Structures of a Tetrathiafulvalene‐Conjugated Bistetracene

A tetrathiafulvalene (TTF)‐conjugated bistetracene was synthesized and characterized in the molecular electronic structures based on the spectroscopic measurements and the single‐crystal X‐ray diffraction analysis. UV/Vis absorption and electrochemical measurements of 5 revealed the considerable electronic communication between two tetracenedithiole units by through‐bond and/or through‐space interactions. The difference in the crystal‐packing structures of 5 , showing polymorphism, results in a variety of intermolecular electronic‐coupling pattern. Of these, the π‐stacking structure of 5 A gave a large transfer integral of HOMOs (97 meV), which value is beyond hexacene and rubrene, thus, quite beneficial to achieve the high hole mobility.     

Assessing the Brønsted Basicity of Diaminoboryl Anions: Reactivity toward Methylated Benzenes and Dihydrogen

Treatment of toluene or p‐xylene with diaminoboryllithium results in consecutive reactions, involving boryl‐anion‐mediated deprotonation at the benzylic position followed by nucleophilic substitution at the boron center, producing benzylborane species and LiH. Diaminoboryllithium also cleaves H₂ heterolytically affording diaminohydroborane and LiH, while the reaction of lithium diaminoboryl(bromo)cuprate with H₂ takes place accompanied by reduction of Cu^I to give diaminohydroborane, LiH, and Cu⁰.     

A Strap Strategy for Construction of an Excited‐State Intramolecular Proton Transfer (ESIPT) System with Dual Fluorescence

An amine‐embedded flexible alkyl strap has been incorporated into an emissive boryl‐substituted dithienylpyrrole skeleton as a new entity of excited‐state intramolecular proton transfer (ESIPT) chromophores. The π‐electron system shows a dual emission, which covers a wide range of the visible region depending on the solvent polarity. The incorporation of the aminoalkyl strap as well as the terminal boryl groups efficiently stabilize the zwitterionic excited‐state species resulting from the ESIPT even in an aqueous medium.     

Biomimetic Total Synthesis of Cyanosporaside Aglycons from a Single Enediyne Precursor through Site‐Selective p‐Benzyne Hydrochlorination

The cyanosporasides A–F are a collection of monochlorinated benzenoid derivatives isolated from the marine actinomycetes Salinispora and Streptomyces sp. All derivatives feature one of two types of cyanocyclopenta[a]indene frameworks, which are regioisomeric in the position of a single chlorine atom. It is proposed that these chloro‐substituted benzenoids are formed biosynthetically through the cycloaromatization of a bicyclic nine‐membered enediyne precursor. Herein, we report the synthesis of such a bicyclic precursor, its spontaneous transannulation into a p‐benzyne, and its differential 1,4 hydrochlorination reactivity under either organochlorine or chloride‐salt conditions. Our bioinspired approach culminated in the first regiodivergent total synthesis of the aglycons A/F and B/C, as well as cyanosporasides D and E. In addition, empirical insights into the site selectivity of a natural‐like p‐benzyne, calculated to be a ground‐state triplet diradical, to hydrogen, chlorine, and chloride sources are revealed.     

Synthesis of 5‐ and 8‐Deoxytetrodotoxin

Tetrodotoxin, a toxic principle of puffer fish intoxication, is one of the most famous marine natural products owing to its complex structure and potent biological activity, which leads to fatal poisoning. Continuous synthetic studies on tetrodotoxin and its analogues to elucidate biologically interesting issues associated with tetrodotoxin have led to the development of versatile routes for a variety of tetrodotoxin derivatives. With the aim of investigating the structure–activity relationship of tetrodotoxin with voltage‐gated sodium channels, this study describes the first total syntheses of 5‐deoxytetrodotoxin, a natural analogue of tetrodotoxin, and 8‐deoxytetrodotoxin, an unnatural analogue, from a newly designed, versatile intermediate in an efficient manner. An estimation of the biological activities of these compounds reveals the importance of the hydroxy groups at the C‐5 and C‐8 positions on the inhibition of voltage‐gated sodium channels.     

Conditions for boundedness into Hardy spaces

We obtain the boundedness from a product of Lebesgue or Hardy spaces into Hardy spaces under suitable cancellation conditions for a large class of multilinear operators that includes the Coifman–Meyer class, sums of products of linear Calderón–Zygmund operators and combinations of these two types.     

Regioselective Synthesis of 6‐Prenylpolyhydroxyisoflavone (Wighteone) and Wighteone Hydrate with Hypervalent Iodine

The oxidative rearrangement of 3′‐iodotetraalkoxychalcone with [hydroxyl(tosyloxy)iodo]benzene, followed by cyclization of the resultant acetal gave 6‐iodotrialkoxyisoflavone. The coupling reaction of the isoflavone with 2‐methyl‐3‐butyn‐2‐ol gave 6‐alkynylisoflavone, whose hydrogenation gave wighteone hydrate. Wighteone was synthesized by dehydration of wighteone hydrate.     

Copper-catalyzed tandem intramolecular cyclization/coupling reaction: solvent effect on reaction pathway

In this study, we developed direct methods for the synthesis of 3-substituted indoles from o-alkynylanilines by utilizing a copper-catalyzed tandem intramolecular cyclization/coupling reaction under mild and simple reaction conditions. Our investigation revealed that choice of the aprotic polar solvents and additives such as camphorsulfonic acid is critical in this reaction.     

Synthesis of N,N‐Dialkyl‐9‐oxoacridine‐10(9H)‐carbothioamides via the Reaction of (2‐Halophenyl)(2‐isothiocyanatophenyl)methanones with Secondary Amines,Followed by Cyclization with NaH

The first preparation of acridin‐9(10H)‐ones carrying a tertiary thiocarbamoyl group at C(10), i.e., N,N‐dialkyl‐9‐oxoacridine‐10(9H)‐carbothioamides 9 , is described. The method is based on the reaction of (2‐halophenyl)(2‐isothiocyanatophenyl)methanones 7 , prepared from (2‐aminophenyl)(2‐halophenyl)methanones 5 by a convenient three‐step sequence, with secondary amines in DMF at room temperature to generate the corresponding thiourea derivatives 8 in situ, which are treated with NaH at 100–120° to provide the desired products in one‐pot reactions in generally good yields.     

Addition of AlkylHalide toward a Tungsten-Phosphorus Double Bond

The terminal phosphide complex of tungsten Cp(CO) 3 W{PN(Me)CH 2 CH 2 PNMe} ( 3 ) prepared from Cp(Sn n Bu 3 )(CO) 2 W{PN(Me)CH 2 CH 2 NMe(OMe)}, BF 3 ;OEt 2 , and NaBPh 4 in situ reacts with PhCH 2 Cl to give cis -Cp(CO 2 )ClW{PN(Me)CH 2 CH 2 NMe(CH 2 Ph)} ( cis-4 ). During the reaction, C--Cl bond addition takes place toward a tungsten-phosphorus double bond. In contrast, isolated 3 does not react with PhCH 2 Cl. Isolated 3 , however, reacts with PhCH 2 Cl in the presence of BPh 3 and BF 3 to give trans-4 and cis-4 , respectively.