Formation of a Substituted Tetrahydrofuran by Formal [2 + 2 + 1] Coupling of an Oxygen Atom with Two Olefins at a Nickel Center

Formation of the tetrasubstituted tetrahydrofuran exo - trans - endo -3-oxapentacyclo[9.2.1.1. 5,8 0. 2,10 0 4,9 ]pentadeca-6,12-diene ( 5 ) has been accomplished by the coupling of an oxygen atom (from nitrous oxide) with two olefins (norbornadiene) at a Ni center. The reaction proceeds via a nickelacyclopentane complex ( 2 ) that is subsequently oxidized by N 2 O to give an isolable oxanickelacyclohexane ( 3 ). Oxidation of 3 with iodine results in formation of the C−O bond of 5 (47% isolated yield) via C,O-reductive elimination.