The dominoKnoevenagelhetero-Diels–Alderreaction of the O-propargylated salicylaldehydes and 4-hydroxycoumarin leads to pyrano[2,3-c]coumarins 3 and pyrano[2,3-c]chromones 4 in high yield in the presence of CuI as a Lewis acid. In all cases, the reaction was shown to exhibit high regioselectivity and form product 3 as main product.
在CuI存在下,O-炔丙基化水杨醛和4-羟基香豆素的多米诺Knoevenagel杂-Diels -Alder反应导致高产率的吡喃并[2,3- c ]香豆素3和吡喃并[2,3- c ]色酮4作为路易斯酸。在所有情况下,反应均显示出较高的区域选择性,并形成产物3作为主要产物。