Synthetic studies on the seven- and eight-membered rings by the intramolecular Nozaki–Hiyamareaction of the allylic phosphates are described. The yield greatly depends on the structure of substrate; however, some complex substrates afforded desired products in high to excellent yield.
The construction of novel borrelidin analogues is reported in which the northern fragment is truncated to a simple hydroxyundecanecarboxylate and the original cyclopentanecarboxylic acid in the southern fragment is replaced with different six-membered rings. The required precursors were prepared by cross metathesis of the appropriate carbocycle-based homoallylic alcohol with crotonaldehyde followed