Lithospermic acid structure

In 1993, Murai reported the reactions of aryl ketones witti ethylene and vinylsilanes to form the product from the addition of the C-H bond ortho to the carbonyl group to the olefin (Equation 18.49). This finding led to subsequent work on the addition of the C-H bonds of a variety of aromatic groups to a series of olefins. Catalysts that react under milder conditions than the original ones and extensions of the C-H activation to intramolecular cyclizations to form heterocyclic structures have made this reaction capable of being used in the synthesis of complex molecules. For example, alkylated diterpe-noids and (+)-lithospermic acid (Equations.18.50 and 18.51) have been synthesized using directed hydroarylation. ... 

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