Tributyltin hydride-mediated radical cyclisation of aldehydes and unsaturated ketones: the synthesis of hydroxy tetrahydrofurans, chromanols and related compounds

The tributyltin hydride-mediated cyclisation of unsaturated ethers bearing an aldehyde or α,β-unsaturated ketone group is reported. Cyclisation proceeds via addition of the tributyltin radical to the carbonyl double bond and the resultant O-stannyl ketyl can add intramolecularly to electron-rich double bonds to form hydroxy tetrahydrofurans, chromanols or related compounds.