In summary, concise formal syntheses of pinnaic acid (1)
and halichlorine (2) have been accomplished by intercepting
the known intermediates 3 and 4, respectively. The unified
strategy for preparing 3 and 4 highlights the utility of olefin
cross metathesis methodologies for the efficient construction
of key olefinic bonds in the arena of natural product
synthesis. Other applications of olefin metathesis to solving
problems in total synthesis are under active investigation,
and the results of these studies will be disclosed in due
course