The Grieco three-component condensation is an organic chemistry reaction that produces nitrogen-containing six-member heterocycles via a multi-component reaction of an aldehyde, an aniline, and an electron-rich alkene. The reaction is catalyzed by trifluoroacetic acid or Lewis acids such as ytterbium trifluoromethanesulfonate (Yb(OTf)3). The reaction is named for Paul Grieco, who first reported it in 1985.