Catalytic Asymmetric Conjugate Allylation of Coumarins

A catalytic asymmetric conjugate allylation was successfully developed to synthesize potential pharmacologically active 4-allyl-2-oxochroman skeletons. A dual activation strategy was employed by using N,N′-dioxide-Yb(OTf)3 to activate coumarins and using (CuOTf)2•C7H8 to activate tetraallyltin via transmetalation, respectively. Good yields and enantioselectivities were obtained under mild conditions.本研究成功开发了一种催化不对称共轭烯丙基化反应，用以合成具有潜在药理活性的4-烯丙基-2-氧代色满（4-allyl-2-oxochroman）骨架。该策略采用双活化模式：分别以N,N′-二氧配体-三氟甲磺酸镱[Yb(OTf)3]活化香豆素类化合物，并通过转金属化过程，以三氟甲磺酸亚铜二聚体·甲苯[(CuOTf)2•C7H8]活化四烯丙基锡。在温和反应条件下，该方法可获得良好的反应收率与对映选择性。