Kuang Y1, Liu X, Chang L, Wang M, Lin L, Feng X.
Org Lett. 2011 Aug 5;13(15):3814-7. doi: 10.1021/ol201312y. Epub 2011 Jun 21.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)•C(7)H(8) to activate tetraallyltin via transmetalation, respectively. Good yields and enantioselectivities were obtained under mild conditions.© 2011 American Chemical Society