No abstract

A new and an efficient method has been developed to synthesize ethyl 4‐(2‐oxo‐2‐arylethyl)‐2‐(trifluoromethyl)‐4H‐chromene‐3‐carboxylate derivatives 3 from 2H‐chromene 1 and aryl acetylene 2 through [3, 3] sigmatropic rearrangement in presence of catalytic amount of BF3.OEt2 (10 mol %).

A convenient method for the activation of aryl‐oximes is reported using 1,1,2,2‐tetrafluoro‐N,N‐dimethylethylamine (TFEDMA) as a scalable and efficient reagent. Aryl‐aldoximes led to aryl‐cyanides while aryl‐ketoximes provided aryl‐amides in moderate to excellent yields. The iminium form of TFEDMA acted as a fluorinated version of the well‐known Vilsmeier reagent. Aryl cyanides and aryl amides are valuable synthetic units in natural products and drug candidates. The cyano group is also useful in polymer chemistry for the preparation of photovoltaic cells and LEDs.

A terse and efficient asymmetric synthesis of tert-butyl 2-(4R, 6R)-6-(2-aminoethyl)-2, 2-dimethyl-1, 3-dioxan-4-yl) acetate is presented, which is a key chiral chain precursor of atorvastatin. This was synthesized from commercially available, non-expensive starting material. The precursor was converted into atorvastatin calcium. The synthesis has the potential for scale-up and could be used to produce atorvastatin calcium on industrial scale.