Manganese(III) or Cobalt(III)-Mediated Oxidative Radical Reactions of Terminal Dienes. One-Pot Synthesis of Bis(dihydrofuran)s

Article abstract of DOI:10.1246/bcsj.64.1097

The reactions of terminal dienes such as 1,4-pentadienes and 1,5-hexadienes with tris(2,4-pentanedionato)manganese(III) () gave α,ω-bis(dihydrofuryl)alkanes (abbreviated bis(dihydrofuran)s, hereafter) in good yields.The reactions with tris(2,4-pentanedionato)cobalt(III) () instead of yielded the same bis(dihydrofuran)s quantitatively.The dienes also reacted with ethyl 3-oxobutanoate in the presence of manganese(III) acetate () or cobalt(III) acetate () to produce the corresponding bis(dihydrofuran)s.The reactions of 1,3-butadienes with the manganese(III) or cobalt(III) complexes afforded only mono(dihydrofuran)s and oxidative rearrangement products, but the corresponding bis(dihydrofuran)s were not formed.The reaction of 1,5-hexadienes with ethyl hydrogen malonate in the presence of did not give bis-annulated products, but mono(γ-lactone)s in moderate yields.The synthetic applications and limitations of the bis(dihydrofuran)s formation are discussed.