The objective of this research proposal is to study the chemistry of vinyl and dienyl ether-iron complexes of general structure: CpFe(CO)2(pi2-omicronl)BF4. Within this program, we propose to establish general methods for the synthesis of classes of isomeric dienyl and polyenyl ether-iron complexes and to illustrate their use in synthesis as vinyl cation synthons and as components in reverse polarity [2+4] cyclo-addition reactions. The discovery of a simple means of preparing optically active vinyl ether-iron complexes of high optical purity and defined absolute configuration provides the background for the second part of the proposal. Our objective here is to examine the use of these systems for effecting efficient and highly flexible asymmetric syntheses of beta-hydroxyaldehydes and acids with complete control of absolute configuration at both the alpha and beta asymmetric centers. An efficient synthesis of the essential amino acid constituent of the immunosuppressive drug cyclosporin is projected, based on this chemistry. In addition, the use of these optically active reagents in assymmetric [2+4] cycloaddition reactions and Claisen rearrangements will be examined. The complexes whose chemistry is the subject of this study will constitute a new class of synthons of unique chemical reactivity in which charge affinity reversal and enantiofacial differentiation are essential and unique features. They should provide valuable new methodology for the synthetic chemist.
