A Pd(II)/Cu(II)-catalyzed chemoselective tandem aerobic cyclization of phenolic olefins leads to [5,6]-bisbenzannelated spiroketals or 2-substituted chromans, wherein it was interestingly found that the presence or absence of base could be responsible for the tunable selectivity. The [5,6]-bisbenzannelated spiroketals were achieved from tandem Wacker cyclization-aroxylation in moderate yields in the absence of base, and 2-substituted chromans were formed through base-mediated Pd(II)/Cu(II)-catalyzed tandem Wacker cyclization-Michael addition in good yields.
在
钯(II)/
铜(II)催化下,
酚类烯烃发生
化学选择性串联有氧环化反应,生成[5,6]-双苯并环化
螺环酮或 2-取代的
铬族化合物,有趣的是,发现碱的存在与否可导致选择性的可调。在无碱条件下,通过串联瓦克环化-甲氧基化反应生成了中等产率的[5,6]-双苯并环化螺酮,而通过碱介导的
钯(II)/
铜(II)催化串联瓦克环化-迈克尔加成反应生成了良好产率的 2-取代色满。