Unsaturated macrocyclic compounds. LXXIII. Synthesis of 1,2-diethynylcyclohexene and its oxidation to a tetradehydro[12]annulene derivative

Abstract

had 96.5% dy composition, was labeled 76.4% at C-3 (2-C1) and 20.1% at C-7 (3-C1).15 The composition of this mixture did not change substantially during two passes through the preparative gas chromatography separation procedures.(15) The propensity of benzonorbornenyl radicals to rearrange has been noted previously.16(16) S.

Synthesis, Characterization and Electronic Structure of Dirhenadehyro[12]annulene Complexes

“…We noted that the parent octadehydro[12]annulene 23 with hydrogen at the vinyl carbons is still unknown experimentally. Alkyl substituted octadehydro[12]annulenes (the substituents are at the vinyl carbons) rapidly decompose on being exposure to air at room temperature . Only octadehydro[12]annulenes with alkynyl substituents or fused with benzo and aromatic moieties at the vinyl carbons are reported to be stable at room temperature .…”

“…Alkyl substituted octadehydro [12]annulenes (the substituents are at the vinyl carbons) rapidly decompose on being exposure to air at room temperature. [18] Only octadehydro[12]annulenes with alkynyl substituents or fused with benzo and aromatic moieties at the vinyl carbons are reported to be stable at room temperature. [14] In contrast, complexes 14 are very stable and can be stored at least one year in a N 2 atmosphere.…”

Ring-Closing Metathesis with Vicinal Dibromoalkenes as Protected Alkynes: A Synthetic Approach to Macrocyclic Enynes

“…Cyclic enynes gained importance with interest in annulene chemistry in the 1960s, and their significance increased as novel biologically active natural products were discovered . Enyne rings constitute the core of potent antitumor antibiotics − and cytotoxic alkaloids .…”

Photoactivated Transition-Metal Triggers for Ambient Temperature Enediyne and Dienyne Cyclization: Ruthenium-η6-Naphthalene Complexes

“…1,2-Bis(prop-1-yn-1-yl)cyclohex-1-ene (4-Me). A 1 M solution of LHMDS (3.00 mL, 3.00 mmol) in THF was added to a stirred solution of 1,2-diethynylcyclohex-1-ene 43 (100 mg, 0.768 mmol) in THF (7.8 mL) at 0 °C. After 20 min at 0 °C, iodomethane (0.300 mL, 4.81 mmol) was added and the solution was warmed to room temperature over the course of 4 h. The reaction mixture was then poured over saturated aqueous NH 4 Cl (20 mL) and extracted with hexanes (2 × 20 mL).…”