Rapid Two‐Directional Synthesis of the F–J Fragment of the Gambieric Acids by Iterative Double Ring‐Closing Metathesis

D-glucal is the starting point for the efficient synthesis of the F–J fragment of the gambieric acids (see scheme). The H-ring diol was subjected to double two-directional alkynyl ether formation, carbocupration ring-closing metathesis, and hydroboration. The tricyclic G–I diol was then converted into the F–J fragment by a sequence that involves another double two-directional ring-closing metathesis reaction. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z501925_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.