Saturday, June 14, 2008

Chemistry Unprotected

The ideal total synthesis of a natural product would proced in one step and in 100% yield from commercially available starting material- this dream is increasingly driving natural products synthesis as a science.
Dr Phil Baran and colleagues at Scripps Institute, La Jolla, California, promises to generate natural products in much larger amounts than conventional methods, making biological testing much easier for drug discovery scientists, Most total syntheses, make liberal use of protecting groups. Adding and removing protecting groups can add many steps to a synthesis, cutting overall yields drastically.
Baran's team have now made a collection of marine natural products without using a single protecting group. Instead, they take advantage of the intrinsic reactivity of the molecule's different functional groups.
Fig(-)-fisherindole to (+)- welwitindolinone The reactions were enatioselective - they made only the preferred mirror-image form, or enantiomer, of the molecule, instead of a racemic mixture containing equal amounts of both enantiomers. They take advantage of the intrinsic reactivity of the molecule's different functional groups.
DOI: 10.1002/anie.200702455