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.

本研究成功开发了催化不对称共轭烯丙基化反应，用于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。本研究采用双活化策略，分别利用N,N′-二氧酰胺配体-三氟甲磺酸镱（N,N′-dioxide-Yb(OTf)3）活化香豆素类化合物（coumarins），并通过金属转移反应（transmetalation），以二(三氟甲磺酸亚铜)·甲苯络合物（(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。