A case study in biomimetic total synthesis: Polyolefin carbocyclizations to terpenes and steroids

This review provides a case study in polyolefin cyclizations in which the total synthesis interaction presents an incontrovertible synergism with an approach having the development of synthetic methods that converge upon the efficient techniques of nature. This polyolefin carbocyclization provides both an enzyme model for remarkable selectivity and a driver for investigations that ask provocative fundamental questions in this area. This review includes a subgroup of polycarbocyclizations to define the relationship that evolved between the purely synthetic work and its biological counterpart. Enumerated and discussed are: stereochemistry of the squalene-sterol cyclization, enzymology: squalene-hopene cyclase, biomimetic total synthesis based on squalene cyclase, epoxysqualene cyclase, and cyclizations based on radical transformations.