Highly Stereoselective Synthesis of a Compound Collection Based on the Bicyclic Scaffolds of Natural Products.

Despite the great contribution of natural products in the history of successful drug discovery, there are significant limitations that persuade the pharmaceutical industry to evade natural products in drug discovery research. The extreme scarcity as well as structural complexity of natural products renders their practical synthetic access and further modifications extremely challenging. Although other alternative technologies, particularly combinatorial chemistry, were embraced by the pharmaceutical industry to get quick access to a large number of small molecules with simple frameworks that often lack three-dimensional complexity, hardly any success was achieved in the discovery of lead molecules.

Branching cascades provide access to two amino-oxazoline compound libraries.

An efficient synthetic access to two amino-oxazoline compound libraries was developed employing the branching cascades approach. A common precursor, that is, chromonylidene β-ketoester was transformed into two different ring-systems, that is, the pyridine and the benzopyrane substituted hydroxyphenones. In further two steps, the ketone moiety in two ring-systems was transformed into an amino-oxazoline ring.

A cyclization-rearrangement cascade for the synthesis of structurally complex chiral gold(I)-aminocarbene complexes.

A facile synthesis of chiral cyclic alkyl aminocarbene-gold(I) complexes from gold-free 1,7-enyne substrates was developed. The novel cyclization-rearrangement reaction sequence is triggered by the addition of (Me2S)AuCl to different 1,7-enynes and leads to structurally unique carbene-gold(I) complexes in high yields. These novel complexes are catalytically active and inhibit the proliferation of different human cancer cell lines.

Concise enantioselective construction of a bridged azatricyclic framework via domino semipinacol-Schmidt reaction.

A TiCl(4)-promoted domino semipinacol-Schmidt reaction of oxaspiropentane-azide provides an easy access to bridged azatricyclic ring systems, which possess the azaquaternary center, present in the immunosupressant FR901483 and platelet aggregation inhibitor daphlongeranine B.