Synthesis of Alkylidene(<i>gem</i>-Difluorocyclopropanes) from Propargyl Glycolates by a One-Pot Difluorocyclopropenation/Ireland–Claisen Rearrangement Sequence

A one-pot difluorocyclopropenation/Ireland–Claisen rearrangement sequence applied to readily available propargyl glycolates was developed as a route toward functionalized alkylidene­(<i>gem</i>-difluorocyclopropanes). This strategy conveniently avoids the isolation of the unstable 3,3-difluorocyclopropenylcarbinyl glycolates arising from the difluorocyclopropenation. The Ireland–Claisen rearrangement proceeds with high diastereoselectivity and chirality transfer to afford alkylidene­(<i>gem</i>-difluorocyclopropanes) incorporating a quaternary stereocenter and a protected glycolic acid moiety, which are useful building blocks for the preparation of functionalized <i>gem</i>-di­fluoro­cyclo­propanes

A Sonogashira Cross-Coupling/5-<i>exo</i>-dig Cyclization/Ionic Hydrogenation Sequence: Synthesis of 4‑Substituted 3‑Azabicyclo[3.1.0]hexan-2-ones from 2‑Iodo­cyclo­propane­carboxamides

A variety of 4-substituted 3-azabicyclo[3.1.0]­hexan-2-ones have been prepared from 2-iodocyclopropanecarboxamides by a three-step sequence involving a copper-free Sonogashira coupling with terminal aryl- or heteroarylalkynes, followed by a 5-<i>exo</i>-dig cyclization and an ionic hydrogenation