A sequential one-pot tandem approach for the synthesis of 4-tosyl-5-aryloxazoles from carboxylic acids

A panoramic view on synthetic applications of α-oxothioamides: a highly regioselective synthesis of 2-acyl-4-(het)arylthiazoles and thioethers

Highly regioselective synthesis of 2-acyl-4-(het)arylthiazoles and thioethers by the reaction between α-oxothioamides and α-bromoketones in the absence of base in DMF and in the presence of triethylamine in acetonitrile, respectively, has been reported. This thiazole synthesis is an important extended work of the Hantzsch thiazole synthesis, which overcomes the drawbacks of earlier reported methods. The probable mechanisms for the formation of thiazoles and thioethers are also presented.

An Alkyne-Metathesis-Based Approach to the Synthesis of the Anti-Malarial Macrodiolide Samroiyotmycin A

We report the first total synthesis of samroiyotmycin A (1), a C₂ -symmetric 20-membered anti-malarial macrodiolide isolated from Streptomyces sp. The convergent synthetic strategy orchestrates bisalkyne fragment-assembly using an unprecedented Schöllkopf-type condensation on a substituted β-lactone and an ambitious late-stage one-pot alkyne cross metathesis-ring-closing metathesis (ACM-RCAM) reaction. The demanding alkyne metathesis sequence is achieved using the latest generation of molybdenum alkylidynes endowed with a tripodal silanolate ligand framework. Subsequent conversion to the required E-alkenes uses contemporary hydrometallation chemistry catalysed by tetrameric cluster [{Cp*RuCl}₄ ].

Unusual structure of a biphenyl fragment: the important role of weak interactions

1,5-Bis([1,1'-biphenyl]-4-yl)-5-hydroxy-3-methylheptane-1,6-dione, C₃₂H₃₀O₃, was investigated by X-ray analysis, quantum chemical calculations and AIM (atoms in molecules) analysis. It was shown that four intramolecular C-H...π forces are established between the two biphenyl fragments. C-H...π interactions lead to a bending of the biphenyl part. The energy of the intramolecular interactions was estimated and the exclusive role of the moment of force was established.