Exploration of the [3 + 2] Cycloaddition Reaction Between Allylstannanes and α,β-Unsaturated Acyliron Complexes

Abstract

The reaction between allylstannanes and α,β-unsaturated acyliron complexes has been investigated. Contrary to the behavior of other α,β-unsaturated carbonyl compounds, α,β-unsaturated acyliron complexes react with allylstannanes to produce predominately cyclopentane derivatives with a high degree of stereoselectivity. The initial cycloadducts contain acyliron and trialkylstannyl functionalities, which are readily converted to ester and alcohol groups, respectively, with complete retention of stereochemistry. Transition state models involving a synclinal orientation of reactants have been proposed to explain the observed stereochemistry. Studies of cyclization reactions of 5-hexenylstannanes have also been described. 1. Introduction 2. Why Examine the Reaction Between Allylstannanes and α,β-Unsaturated Acyliron Complexes in the First Place? 3. Optimization of the Reaction Between Allyltributyltin and Acryloyldicarbonyl(η-cyclopentadienyl)iron (2). 4. Will Allyltributyltin React with Other α,β-Unsaturated Acyliron Complexes in the Same Manner? 5. Will Acryloyliron Complex 2 React Similarly with Other Allylic Tributylstannanes? 6. Reactions in which Both Cycloaddition Partners Bear Additional Substituents 7. What Do Other Allylmetal Complexes Do? 8. Development of Methods for Conversion of the Metals to Simpler Functional Groups 9. Development of New C-Sn Bond Cleavage Reactions 10. Assignment of Stereochemistry 11. What Is the Mechanism of the Reaction? 12. How Do We Explain the Observed Stereoselectivity? 13. What's So Great About This Model? 14. Why Do α,β-Unsaturated Acyliron Complexes Behave So Differently from Other α,β-Unsaturated Carbonyl Compounds? 15. How Do We Explain Those Cases Where Open-Chain Products Are Obtained? 16. Summary and Outlook