The first method for the [3 + 2] annulation of donor acceptor aminocyclopropanes with aldehydes is reported. The reaction is catalyzed by iron trichlorlde on alumina in yields up to 99% and with excellent cis selectivities (up to >20:1) and represents a stereoselective and atom economic access to valuable 2-aminotetrahydrofurans, which constitute the core of DNA and RNA.