Intramolecular reaction

About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.

Cyclization of diacetylenes to E,E exocyclic dienes. Complementary procedures based on titanium and zirconium reagents

Abstract: La cyclisation intramoleculaire de composes diyniques a ete effectuee en utilisant l'une des combinaisons de reactifs: Cp 2 TiCl 2 /PMePh 2 /Na(Hg) ou Cp 2 ZrCl 2 /Mg/HgCl 2

Reduction of the Aqueous Mercuric Ion by Sulfite: UV Spectrum of HgSO3 and Its Intramolecular Redox Reaction

Abstract: Aqueous hydrogen sulfite reacts with Hg2+ to form, in the absence of excess HSO3-, the HgSO3 complex, observed here for the first time. Its UV spectrum is described by e(234 nm) = (1.57 ± 0.05) × 104 M-1 cm-1. HgSO3 decomposes in an intramolecular redox reaction which is kinetically first-order. The rate constant is independent of [Hg2+], [HSO3-], [O2(aq)], and ionic strength. An acid-assisted pathway becomes significant at pH ≤ 1, attributed to the contribution of HgSO3H+. The rate of the intramolecular reaction of HgSO3 was measured by trapping the Hg0 product as Hg22+; the value of the rate constant is k0 = (0.0106 ± 0.0009) s-1 at 25.0 °C, pH 3. The activation parameters for pH 3, ΔH‡ and ΔS‡, are (105 ± 2) kJ/mol and (68 ± 6) J/mol·K, respectively, consistent with a unimolecular bond cleavage mechanism. A pathway involving H2O-induced concerted 2e- transfer is proposed.

A highly enantioselective intramolecular Heck reaction with a monodentate ligand.

Abstract: An efficient enantioselective intramolecular Heck reaction of cyclohexadienones, using readily available and modular TADDOL-based mono- and bidentate phosphoramidites as chiral ligands and not requiring any additives, has been developed. Excellent enantioselectivities up to 96% ee are reached for the first time in a Heck reaction with monodentate ligands.