2-(2-Alkoxycarbonyl-1-arylamino-1-propenyl)benzimidazolium and 5-(2-alkoxycarbonyl-1-arylamino-1-propenyl)triazolium salts were synthesized in good yields from the reaction of benzimidazole and triazole carbenes with ketenimines. Upon treatment with a base, both salts were converted into novel 1,3-dipoles which underwent [3+2] cycloaddition reactions with electron-deficient alkynes and allenes ...

It is well established that human serum paraoxonase (PON1) catalyzes the hydrolysis of organophosphate insecticides and nerve agents, as well as that of a number of aromatic carboxylic acid esters. Our laboratory has recently found a new class of PON1 substrates that includes at least 30 lactones and cyclic carbonate esters. The lactone substrates vary in their ring size from 4 to 7 atoms. Subs...

Irradiation of &methyl spiro [2.5] oct-7-en-4-one through its singlet excited state resulted in the formation of 4-methyl spirO [2.5] oct-4-en -6-one. We have used the cyclopropyl moiety in the molecule as a probe to study the operating mechanism in the photochemistry of ?, ?-unsaturated compounds. The results showed that this photoisomerization probably occurs through a concerted process.

The collective total synthesis of Lycopodium alkaloids (+)-fawcettimine (1), (+)-fawcettidine (2), (+)-alopecuridine (4), (-)-lycojapodine A (6), and (-)-8-deoxyserratinine (7) has been accomplished from a common precursor (15) based on a highly concise route inspired by the proposed biosynthesis of the fawcettimine- and serratinine-type alkaloids. An intramolecular C-alkylation enabled efficie...

Hole transporting materials (HTMs) play essential roles in facilitating hole extraction and suppressing recombination lead halide perovskite solar cells (PSCs). High levels of p-doping HTMs is necessary for achieving high device performance, attributed to an increased electrical conductivity. In this work, we provide evidences that the poor performance PSCs with low doping (i.e., 4 mol% spiro-O...

Plants have a long history as therapeutics in the treatment of human diseases and have been a continuous source of inspiration for the development of new medicines. Among them, the genus Inula (Asteraceae) comprisesmore than 100 species, many of which are widely used in traditional medicine for a variety of biological purposes including anti-inammatory, anti-cancer and antibacterial activities...

The N-heterocyclic carbene catalyzed annulation of benzofuran-2,3-diones and enals via homoenolate intermediates is described. The reaction provided a direct and efficient method for the synthesis of spiro-bis-lactones. The ketone-carbonyl group annulated products and the ester-carbonyl group annulated products can be obtained as major products with good yields by convenient catalyst regulation...

Electrophilic ring opening of spiro-cyclopropanecarboxylated sugars followed by reaction with DBU revealed interesting ring-contraction and ring-expansion reactions depending on the substrate and the kind of hydroxyl protective group present adjacent to the spiro center. A stereoselective method for accessing a new class of carbon chain extended keto-furanoses and C-glycosylated bicyclic compou...

Chiral spiro phosphorus ligands including monophosphoramidites and diphosphines, which contained 1,1'-spirobiindane as a backbone, were designed and synthesized. These spiro ligands were proven to be highly efficient for rhodiumand ruthenium-catalyzed asymmetric hydrogenations of prochiral olefins and ketones with excellent enantioselectivities.

A new approach towards the synthesis of indole derivatives via triflic acid-promoted cycloisomerization with rearrangement of 2-(alkyn-1-yl)phenyl isothiocyanates and 2-(alkyn-1-yl)phenyl isocyanates has been achieved. By this methodology, structurally diverse types of indole derivatives such as thieno- and furo-indoles, spiro-indolethiones, spiro-oxindoles, and 3-alkylidene-oxindoles were synt...