Reaction of methylenecyclopropanes with tetracyanethylene. New cycloaddition involving three-and two-carbon units

Structure, Synthesis, and Chemical Reactions of Fluorinated Cyclopropanes and Cyclopropenes

“…Berson and later Little and co-workers have demonstrated a wide variety of intra-and intermolecular "cycloaddition" reactions of TMM-diyls of highly strained methylene cyclopropanes, 128,129 but there have been few reports of relatively "simple" methylenecyclopropanes undergoing such trapping reactions. [130][131][132] Fluorines seem to help in that regard. When a fluorinated methylenecyclopropane bears sufficiently stabilizing groups at the pivot carbon, there can be sufficient diyl present, in some systems even at room temperature, for TMM-diyl trapping to occur.…”

Hydrotrifluoromethylation of Unactivated Alkenes and Alkynes Enabled by an Electron-Donor–Acceptor Complex of Togni’s Reagent with a Tertiary Amine

“…An EDA complex is an association of two molecules, named an electron donor and an electron acceptor . Although the photophysical properties of EDA complexes have been extensively studied, EDA complex-enabled chemical synthesis remains largely unexplored because the electron transfer from the donor to the acceptor is fast and reversible. − Recently, useful photochemical transformations, such as cycloaddition, alkylation, and arylation of aromatic compounds, have been achieved mediated by EDA complexes . Despite these promising advances, EDA complex-enabled synthetic chemistry is still in its infancy and in need of further investigated.…”

Thermally‐Induced Intramolecular [4+2] Cycloaddition of Allylamino‐ or Allyloxy‐Tethered Alkylidenecyclopropanes

“…Next, we focused on investigating the mechanism of this cycloaddition reaction. According to the previous reports, [7a,8a,9a,10,11] an initially proposed reaction mechanism for this cycloaddition reaction is shown in Scheme 2. Firstly, substrate 1 proceeds through a [4+2] Diels‐Alder reaction process to afford intermediate A upon heating at high temperature.…”

“…Therefore, ACPs can be used as a good carrier of the three‐membered ring to use their connected exocyclic double bonds undergoing the cyclization reaction with dienes, dipoles and olefins via [4+2], [7] [3+2], [8] [2+2] [9] and the other cycloaddition reactions. With regard to this aspect, in 1971–1972, Baldwin, Pasto and Noyori groups reported the intermolecular [4+2] cycloaddition reaction between diarylmethylenecyclopropanes and tetracyanoethylene (TCNE) successively [7a,8a,9a] . This cycloaddition reaction generated the relatively unstable cycloaddition product, affording the naphthalene derivatives through the process of losing one molecule of HCN and the ring‐opening rearrangement of three‐membered ring (Scheme 1, eq 1).…”