Samarium diiodide-promoted intramolecular radical cyclization of (eta(4)-diene)Fe(CO)(3) complexes bearing keto side chains

Reaction of samarium diiodide with (eta(4)-cyclohexadiene)Fe(CO)(3) complex es bearing keto side chains in THF/HMPA/t-BuOH gives fused bicyclo[4.3.0]no nenol derivatives, whereas (eta(4)-cycloheptadiene)Fe(CO)(3) analogues prod uce a bicyclo[5.3.0]decenol ring skeleton. The iron-mediated intramolecular radical addition allows for the direct stereocontrol of three contiguous s tereogenic centers of these fused bicyclic skeletons. Under the same reacti on conditions, intramolecular ketyl radical cyclization of acyclic (eta(4)- 1,3-butadiene)Fe(CO)(3) complexes with keto side chains at the terminal pos ition of the diene ligands furnishes disubstituted cyclopentanol and cycloh exanol derivatives with excellent diastereoselectivity.