Qitao Tan

• Dr.
• Professor (Associate) at Shanghai University

An unprecedented generation of nitrile oxides was developed from α-keto acids and copper nitrate through a novel carbon–carbon bond cleavage mode, affording pharmacologically interesting fused isoxazolines via 1,3-dipolar cycloadditions.

An eco‐friendly and noble‐metal‐free formal [4+2] cycloaddition reaction was developed for the efficient synthesis of biologically interesting poly‐substituted pyridines from easily available ketones and imines, whereby two sequential C−C bonds are formed. The given approach features a unique synthetic strategy of imines and ketones with wide subst...

Unsymmetrical disulfides have been effectively prepared through thiol exchange with symmetrical disulfides employing a simple PdCl2/DMSO catalytic system. The given method features excellent functional group tolerance, a broad substrate scope, and operational simplicity. This reaction is especially useful for late-stage functionalization of bioacti...

Functionalization of polycyclic aromatic hydrocarbons (PAHs) with functional groups is essential for tuning the optoelectronic properties, solid stacking and solubility. α‐Iminonitriles are composite functional groups (CFGs) containing imine (C=N−R) and nitrile (CN) moieties with strong electron‐withdrawing character and good stability, which could...

An efficient silver-assisted oxidative coupling of simple ethers with tert-butyl isocyanide was realized in the presence of DDQ. The direct synthesis of high density functional β-carbonyl α-iminonitriles was achieved in a single step with high yields through the synergetic cascade isocyanide insertion into C(sp3)-H bond, where the isocyanide was us...

Heterocycles are prevalent constituents of many marketing drugs and biologically active molecules to meet modern medical challenges. Isocyanide insertion into C(sp3)-H bonds is challenging especially for the construction of quaternary carbon centers. Herein, we describe an efficient strategy for the synthesis of α-iminonitrile substituted isochroma...

A synthesis of tellurium-embedded π-extended aromatics from tellurium powder and readily available cyclic diaryliodonium salts has been developed. The versatility of this method has been demonstrated by the synthesis of various functionalized dibenzotellurophenes (DBTe's), a ladder-type π-system, and a heterosumanene. These compounds demonstrated g...

A copper nitrate-mediated [2 + 2 + 1] cycloaddition reaction was developed for the expedient synthesis of pharmacologically interesting 3-aryl substituted isoxazolines and isoxazoles through C[double bond, length as m-dash]C bond cleavage. Copper nitrate is employed as a reaction promoter and precursor of nitrile oxides. The given approach features...

A palladium-catalyzed multicomponent reaction of alkynes, carboxylic acids, and isocyanides has been developed with the assistance of silver salt under mild conditions. Highly functionalized captodative olefins are synthesized efficiently by this method, which can find many applications as versatile synthons in organic synthesis.

A palladium-catalyzed synthesis of dibenzothiophenes from 2-biphenylthiols is described. This highly efficient reaction employs a simple PdCl2/DMSO catalytic system, in which PdCl2 is the sole metal catalyst and DMSO functions as an oxidant and solvent. This transformation has broad substrate scope and operational simplicity and proceeds in high yi...

An efficient, copper-catalyzed [3+1+1] cycloaddition reaction was developed for the expedient synthesis of pharmacologically interesting polysubstituted pyrroles from easily available nitrones and α-acidic isocyanides. The given approach features a new mode of cycloaddition between nitrones and isocyanides with wide substrate scope, good functional...

Buckybowls, which are represented by sumanene and corannulene, have attracted considerable attention for their unique bowl structures and interesting physicochemical properties. However, still few heteroatom-doped buckybowls have been reported to date. Here we show the successful synthesis of triazasumanene, an isoelectronic heteroanalogue of suman...

The synthesis of an iodine-doped sumanene, which represents the first example of halogen-doped buckybowls, is described. Pristine trithiasumanene, trisilasumanene and hitherto unknown parent triselenasumanene, three interesting heterobuckybowls of significant synthetic challenges, were efficiently prepared from the iodine-doped sumanene through non...

A three-step synthesis of C3-symmetric trisilasumanene and trigermasumanene, heteroanalogues of the π-bowl sumanene, was achieved using a threefold rhodium-catalyzed cyclodehydrogenation of Si/Ge-H and C-H bonds as the key step. Trigermasumanene was proven to adopt a planar geometry by single crystal X-ray diffraction for the first time. The optica...

A novel and direct approach to alkyl/aryl heteroarene sulfonic esters using copper sulfate as the environmentally benign inorganic sulfonation reagent was first realized with the aid of isocyanide. A variety of heterocycles reacted to afford the corresponding sulfonic esters through C−H functionalization. In this transformation, the otherwise inert...

A novel and direct approach to alkyl/aryl heteroarene sulfonic esters using copper sulfate as the environmentally benign inorganic sulfonation reagent was first realized with the aid of isocyanide. A variety of heterocycles reacted to afford the corresponding sulfonic esters through C−H functionalization. In this transformation, the otherwise inert...

The development of new synthetic methodologies often enables or facilitates the synthesis of enormous potentially useful compounds. The past decade has witnessed significant advances in the field of CH bond functionalization, and it has recently emerged as an ideal and straightforward method for the formation of carbon–carbon or carbon–heteroatom b...

C3-symmetric chiral triaryltriazasumanenes were successfully prepared in good yields by Pd-catalyzed cross-coupling reactions of chiral tris(methylthio)triazasumanene with various arylboronic acids. These chiral triaryltriazasumanenes showed very stable bowl chirality without racemization at room temperature. Single-crystal X-ray crystallography of...

An efficient copper-promoted C(sp2)-H bond amination was developed to afford 1H-indazoles and 1H-pyrazoles in moderate to excellent yields from easily accessible hydrazones. This process tolerated a variety of functional groups and afforded the corresponding 1H-indazoles and 1H-pyrazoles under mild conditions.

A four-step synthesis of the C3-symmetric parent 1,5,9-triazacoronene (TAC) and its derivatives was achieved using a three-fold Bischler-Napieralski cyclization as the key step. The single-crystal X-ray diffraction of 1b (R = n-Bu) demonstrates that the azacoronene core is perfectly co-planar and the molecules adopt a favorable 2-D "brick-wall" arr...

A novel direct transformation of hydrazones to acyloxylated pyrazoles by copper-catalyzed regioselective olefinic C(sp2)–H bond cycloamination and acyloxylation was developed under mild conditions, which combines the formation of the pyrazole skeleton and installation of an acyloxyl group in a single step, using facile carboxylic acids as the acylo...

No abstract is available for this article.

An efficient copper‐catalyzed tandem aerobic oxidative annulation and carbon‐carbon bond cleavage reaction was developed from easily accessible arylacetamides, which provides a direct approach for the domino synthesis of a vast array of tricyclic or tetracyclic fused quinazolinone alkaloid structures. A plausible reaction mechanism is proposed invo...

An efficient and mild synthesis of imidazo[1,2‐a]pyrimidine derivatives has been developed from readily available pyrimidyl arylamines or enamines through a hypervalent iodine‐promoted intramolecular C–H bond cycloamination reaction. This protocol allows for the facile construction of biologically active bicyclic imidazo[1,2‐a]pyrimidine skeletons...

An efficient palladium-catalyzed oxidative annulation reaction was developed through sequential isocyanide insertions into N-H and O-H bonds of hydrazides, which provides an efficient access to valuable 2-amino-1,3,4-oxadiazoles and their derivatives.

An efficient rhodium-catalyzed regioselective C-N bond formation of azo compounds was developed in good to excellent yields through C-H bond functionalization by using azides as nitrogen sources. Alkyl, aryl and sulfonyl azides could be efficiently assembled in this reaction with excellent functional group tolerance.

An efficient rhodium-catalyzed regioselective C-H bond cyanation of arenes was developed using tert-butyl isocyanide as the cyanide source. A wide range of (hetero)aryl and cycloalkenyl nitriles could be afforded with high regioselectivity and good functional group tolerance.

A copper-mediated multi-component reaction was developed through isocyanide insertion into N-H bonds of less active secondary arylamines. This approach leads to an efficient synthesis of unsymmetrical tetrasubstituted ureas in one pot.

Nature Communications 3 : Article number: 891 10.1038/ncomms1896 ( 2012 ); Published: 12 June 2012 ; Updated: 8 January 2013 . In this Article, the space group for the crystal structure of compound 6 is noted as being triclinic P1.

Bowl-shaped aromatic compounds, namely buckybowls constitute a family of curved polycyclic aromatic carbons along with fullerenes and carbon nanotubes. Doping of heteroatoms to the carbon frameworks of such aromatic compounds drastically modulates their physical and chemical properties. In contrast to nitrogen-doped azafullerenes or carbon nanotube...

An asymmetric synthesis of chiral intermediate 3 for (-)-oseltamivir phosphate has been accomplished from chiral building block 1, which was prepared by catalytic asymmetric synthesis.

A facile and short synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol (1) has been achieved in high yield starting from 4,5-epoxycyclohex-1-ene by using a catalytic asymmetric allylic oxidation reaction.

Asymmetric desymmetrization of allylic oxidation of 4,5-epoxycyclohex-1-ene (1) took place in the presence of 2.5 mol % of Cu(CH(3)CN)(4)PF(6) and 3 mol % of chiral N,N-bidentate ligand (S)-2 to afford (3S,4S,5S)-3-benzoyloxy-4,5-epoxycyclohex-1-ene (3) in 84% ee, which was increased up to >99% ee after recrystallization of 3-4'-nitrobenzoyloxy der...

New N,N-bidentate Schiff base ligands containing the 2-quinolyl moiety proved to be effective in conferring high reactivity and moderate to high enantioselectivity (up to 84% ee) to the copper(I)-catalyzed asymmetric allylic oxidation of various cylic olefins with tert-butyl perbenzoate. As copper(I) sources, we employed copper(II) triflate/phenylh...

A catalytic amount (1-2 mol%) of palladium(II) acetate was found to work as a catalyst for the cyanation of di- and trisaccharidic per-O-acetylglycals with trimethylsilyl cyanide to afford di- and trisaccharidic 2-enopyranosyl cyanides in high yields and in moderate stereoselectivities.

Biphenyl-bisoxazoline ligands conveniently synthesized from β-DDB have been exploited in asymmetric pinacol coupling reaction for the first time. The pinacol products were obtained with good yields, high diastereoselectivities and good enantioselectivities (up to 83%e.e.). The stereochemistry of the diol products was dominated by the steric structu...

Novel bis(oxazoline) ligands derived from camphoric acid were prepared and applied to Cu-catalyzed asymmetric cyclopropanation of styrene or 1,1-diphenylethylene with diazoacetate. Good ee values (up to 81%) were obtained for 1,1-diphenylethylene; however, the enantioselectivities for styrene were poor. The chirality of the oxazolyl group dominated...

Biphenyl lignan (ß-DDB) (2), an effective drug in the treatment of hepatitis, was for the first time asymmetrically synthesized via a chiral oxazoline mediated Ullmann coupling. The two enantiomers of ß-DDB have been obtained in this way by using the optically pure amino alcohols L-valinol and D-valinol, respectively. However, attempts to synthesiz...

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From easily available camphoric acid, endo‐2‐hydroxyepicamphor 1 and endo‐3‐hydroxycamphor 2 have been prepared as a mixture which can be further separated to pure forms. This method offers a convenient synthesis of 1 and 2.

Camphorquinone (1), an important fine chemical and medicinal product derived from camphor, was efficiently synthesized from easily available camphoric acid (2). The key steps include acyloin condensation using Me3SiCl as a scavenger of alkoxides and oxidation of the bis(trimethylsilyl) derivative 4 by bromine in CCl4. The new method offers an effic...

A series of copper(Schiff-base) complexes with two chiral centers derived from 1,2-diphenyl-2-amino-ethanol were synthesized and applied to catalyze the asymmetric cyclopropanation of ethenes with diazoacetates. A mechanism that can explain the observed results was proposed. Some of these complexes were also efficient catalysts for asymmetric cyclo...