Abstract
Allylic alcohols form perrhenate esters upon reaction with Re2O7 or HOReO3. These species undergo nonstereospecific and nonregiospecific alcohol-transposition reactions through cationic intermediates. Sequencing these nonselective processes with reversible trapping by electrophiles results in cyclization reactions where regio- and stereocontrol are dictated by thermodynamics. The cationic intermediates can also be utilized as electrophiles in intra- or intermolecular dehydrative reactions with nucleophiles. These processes serve as the basis for applications in catalytic syntheses of a wide range of heterocyclic and carbocyclic structures that often show considerable increases in molecular complexity. This Account describes a sequence of events that started from a need to solve a problem for the completion of a natural product synthesis and evolved into a central element in the design of numerous new transformations that proceed under mild conditions from readily accessible substrates.
1 Introduction
2 Exploratory Studies
3 Application to Spiroketal Synthesis
4 Reactions with Epoxides as Trapping Agents
5 Development of Dehydrative Cyclizations
6 Bimolecular Reactions
7 Spirocyclic Ether Formation
8 Conclusions
Key words
allylic alcohols - transposition - perrhenate esters - rhenium catalysis - stereoselectivity - molecular complexity