Cyclase Mediated Synthesis of Terpenoids

Abstract

A review with 23 refs. Oxidosqualene-lanosterol cyclase (OSLC) from sonicated baker's yeast has been employed for the stereoselective synthesis of lanosterol and its analogs. An extensive study of the enzyme's reactivity profile has been conducted using surrogate substrates displaying structural modifications at both termini of the squalene backbone. Addnl. probes for assessing the enzyme's tolerance with respect to structural modification of the internal portion of the hydrocarbon system have also been investigated. The successful cyclization of such compds. has resulted in a biocatalytic synthesis of remote functionalized sterols. Furthermore, a tentative model for predicting the substrate flexibility for OSLC is presented. Work toward developing an enzymic synthesis of the biol. important pregnane steroid system is discussed along with the progress toward developing a cyclase mediated route to the asym. synthesis of bicyclofarnesyl terpene ring systems. This latter approach rests on the ability of OSLC to cyclize modified farnesyl derivs. as a direct means for the stereoselective assembly of the bicyclic framework. [on SciFinder (R)]