Stereocontrolled preparation of stereocomplementary regioisomeric tricarbonyliron complexes in enantiopure form

The use of ultrasound to form ferralactone complexes from an enantiomerical ly pure allylic epoxide with an adjacent hydroxymethyl substituent affords a pair of stereocomplementary isomers that offer a regioconvergent route to the same chiral pentadienyliron complex. The enantiomeric purity, CD prope rties, and absolute configurations of intermediate eta(4)-diene complexes a re reported, and X-ray diffraction analysis of a pair of rearranged ferrala ctone complexes establishes their relative stereochemistries, and confirms their absolute stereochemistries. (C) 2000 Elsevier Science Ltd. All rights reserved.