Abstract
New methods for the construction of quaternary carbon centres, with organoiron and organomolybdenum chemistry, are presented. Regiocontrolled addition of tin enolates to substituted cyclohexadienyliron tricarbonyl complexes leads to a new approach to trichothecene synthesis, illustrated by a short total synthesis of ( + )- trichodiene. A new coupling reaction of alkenes and diene-Fe(CO)
3
units is described, the outcome of which is equivalent to a [6 + 2] ene reaction. Some applications of arene-manganese tricarbonyl complexes to the preparation of substituted diaryl ethers are discussed, in the context of synthetic approaches to the glycopeptide antibiotics ristocetin A and vancomycin. Finally, stereocontrolled nucleophilic addition to cycloheptadienyliron complexes is illustrated and applied to a synthesis of the Prelog-Djerassi lactone.