Vinylogous Fluorine Stabilizing Effect Enables Rational Design of a Novel Donor‐Acceptor Cyclopropane and Its Applications in 3+2 Cycloaddition Reaction and Ring‐Opening Polymerization†

Comprehensive Summary Discovery of unprecedented donor‐acceptor patterns can essentially enrich the chemistry of donor‐acceptor cyclopropanes. We herein introduce a concept of vinylogous fluorine stabilizing effect, which guides rational design of a novel donor‐acceptor cyclopropane employing gem ‐difluorovinyl group as the electron donor, namely dFVCP. Application of such dFVCPs in a 3+2 cycloaddition with aldehydes and a controlled ring‐opening polymerization by a Mg(OTf) 2 /DIPEA/C(sp 3 )‐H initiator system have been demonstrated, providing direct access to fluorine‐containing tetrahydrofurans and all‐carbon main‐chain polymers.