Organometallic compounds in organic synthesis—part 17: Reactions of tricarbonylcyclohexadienyliron salts with o-silylated enolates,allyl silanes and aspects of their synthetic equivalents

Efficient CC bond formation results during reactions of O-silylated enolates and allytrialkysilanes with a range of tricarbonylcyclohexadienyliron salts to give tricarbonylcyclohexadieneiron complexes in good to excellent yields. This represents a new and efficient type of conversion of aldehydes, ketones, esters and lactones, through enol TMS ethers, into synthetically useful products. An advantage of the allylsilane process is that CC formation occurs at the end of the double bond remote from the silane group. The cations employed can be defined as synthetic equivalents of the 5-cation of substituted cyclohexadienes, or of the 4-cation of cyclohex-2-enones, or alternatively of specifically substituted aryl cations, dependent on their structures and the subsequent treatment of the reaction product.