Additions of organomanganese reagents to conjugated nitroolefins
摘要:
Additions of organomanganese reagents to aromatic and aliphatic conjugated nitroolefins were examined for the first time. In most cases reaction proceeded rapidly at -30 degrees C. Unlike Mn reagents lacking beta-hydrogens (Me, Ph), which lead to oxidative coupling and reductive dimerisation of nitrostyrenes, benzylmanganese chloride gives 1,4-addition in yields exceeding Grignard or Cu-assisted additions. At 0 degrees C alkyl(Bu, Pr)-manganese reagents undergo an addition-migration-elimination process with nitrostyrenes providing a convenient and stereospecific entry into arylated trans-olefins.