Results from the systematic exploration of the scope of the intramolecular [4+2] cycloaddition of conjugated enynes revealed that the reaction is quite general. The synthetic utility of the intramolecular enyne cycloaddition for the synthesis of substituted polycyclic aromatic and dihydroaromatic heterocycles has been demonstrated. In the course of our investigation, we examined a variety of fe...

A Pd(0)-catalyzed intramolecular Heck-type reaction of oxime ether has been developed, providing convenient access to heterocyclic oximes.

The synthesis of 6H-benzo[c]chromenes from unactivated 2-bromo aryl benzyl ethers was studied through two approaches: (i) the transition-metal-free intramolecular dehydrohalide coupling via intramolecular homolytic aromatic substitution; and (ii) the intramolecular cyclization via direct C–H arylation catalysed by PdCl2(MeCN)2. Having developed the most efficient method, a 17-membered chromene ...

p-Nitrophenyl N-(2-mercaptophenyl)-N-methylcarbamate cyclizes rapidly at 25' to N-methylbenzothiazolone with release of p-nitrophenol. The pH-rate constant profile is sigmoidal with pK,,, = 8.7. The effective molarity of the neighboring sulfhydryl group is 1.4 X los M in comparison with bimolecular attack of thiols on p-nitrophenyl N-methyl-Nphenylcarbamate. The pH-rate constant profile for cyc...

The direct synthesis of pyrrolo[2,3- b ]indoles is developed using a Cu/Fe cocatalyzed intramolecular cycloamination α-indolylhydrazones. This transformation proceeds cleanly and selectively at 50 °C in air, with water as the only reaction medium.

Total syntheses of alkaloid 251F (1), a natural product detected from the skin extracts of the dendrobatid frog species Minyobates bombetes, and its racemic 3-desmethyl derivative (2) are reported. A Diels-Alder reaction initiated both syntheses and established four consecutive stereogenic centers. Important to the synthesis of 2 was a first-generation ozonolysis/olefination/aldol strategy to c...

A new thiosemicarbzone compound was prepared by the reaction of acenaphthenequinone and thiosemicarbazide (1:1 molar ratio) in absolute methanol at 70°C. The crystal structure of this compound, acenaphthenequinone thiosemicarbazone mono methanol, was determined by X-ray crystallography. The unit cell parameters are as follows: a = 7.0384(14) Ǻ, b = 14.202(3) Ǻ, c = 14.270(3) Ǻ, β = 104.26(3)°. ...