Lewis-acid-mediated ring-exchange reaction of dihydrobenzofurans and its application to the formal total synthesis of (−)-quinocarcinamide

Asymmetric Total Synthesis of (+)-Quinocarcinamide

The first asymmetric total synthesis of (+)-quinocarcinamide (3), an enantiomer of the natural oxidation product from antitumor antibiotic (-)-quinocarcin (1), is described. Key steps include an iridium-catalyzed asymmetric allylic amidation of racemic alcohol 9, olefin cross-metathesis followed by a S_N2' to forge tetrahydroisoquinoline, and stereocontrolled 1,3-dipolar cycloaddition between a facilely generated azomethine ylide and tert-butyl acrylate to construct the diazabicyclo[3.2.1]octane ring.

Asymmetric Synthesis of Isoquinoline Alkaloids: 2004-2015

In the past decade, the asymmetric synthesis of chiral nonracemic isoquinoline alkaloids, a family of natural products showing a wide range of structural diversity and biological and pharmaceutical activity, has been based either on continuation or improvement of known traditional methods or on new, recently developed, strategies. Both diastereoselective and enantioselective catalytic methods have been applied. This review describes the stereochemically modified traditional syntheses (the Pictet-Spengler, the Bischler-Napieralski, and the Pomeranz-Fritsch-Bobbitt) along with strategies based on closing of the nitrogen-containing ring B of the isoquinoline core by the formation of bonds between C₁-N₂, N₂-C₃, C₁-N₂/N₂-C₃, and C₁-N₂/C₄-C_4a atoms. Methods involving introduction of substituents at the C1 carbon of isoquinoline core along with syntheses applying various biocatalytic techniques have also been reviewed.

Gold catalysis in total synthesis – recent achievements

The most recent achievements of gold catalysed transformations applied in total synthesis of natural products are reviewed and analysed.