44607-51-4Relevant articles and documents
One-pot Synthesis of 1,3-Butadiene and 1,6-Hexanediol Derivatives from Cyclopentadiene (CPD) via Tandem Olefin Metathesis Reactions
Turczel, Gábor,Kovács, Ervin,Csizmadia, Eszter,Nagy, Tibor,Tóth, Imre,Tuba, Robert
, p. 4884 - 4891 (2018/09/25)
A novel tandem reaction of cyclopentadiene leading to high value linear chemicals via ruthenium catalyzed ring opening cross metathesis (ROCM), followed by cross metathesis (CM) is reported. The ROCM of cyclopentadiene (CPD) with ethylene using commercially available 2nd gen. Grubbs metathesis catalysts (1-G2) gives 1,3-butadiene (BD) and 1,4-pentadiene (2) (and 1,4-cyclohexadiene (3)) with reasonable yields (up to 24 % (BD) and 67 % (2+3) at 73 % CPD conversion) at 1–5 mol % catalyst loading in toluene solution (5 V% CPD, 10 bar, RT) in an equilibrium reaction. The ROCM of CPD with cis-butene diol diacetate (4) using 1.00 - 0.05 mol % of 3rd gen. Grubbs (1-G3) or 2nd gen. Hoveyda-Grubbs (1-HG2) catalysts loading gives hexa-2,4-diene-1,6-diyl diacetate (5), which is a precursor of 1,6-hexanediol (an intermediate in polyurethane, polyester and polyol synthesis) and hepta-2,5-diene-1,7-diyl diacetate (6) in good yield (up to 68 % or TON: 1180). Thus, convenient and selective synthetic procedures are revealed by ROCM of CPD with ethylene and 4 leading to BD and 1,6-hexanediol precursor, respectively, as key components of commercial intermediates of high-performance materials.
Electron Delocalisation and Stabilisation in Heptatrienyl and Polyenyl Radicals
Green, Iain G.,Walton, John C.
, p. 1253 - 1258 (2007/10/02)
Heptatrienyl radicals were generated by hydrogen abstraction from hepta-1,3,6-triene with t-butoxyl radicals and observed by e.s.r. spectroscopy.The hyperfine splittings of heptatrienyl and other polyenyl radicals indicate that spin density is not uniformly distributed along the chain but more concentrated around the central region of the structure.Semi-empirical SCF MO calculations agree with this result and also show that most radical character is associated with the central region.The stabilisation energies (SE) of polyenyl radicals increase with chain lenght and are related to the hydrogen hyperfine splittings (G) of SEESR/kJ mol-1 = 375 +/- 4 - (272+/-)log101)/G> (i) the terminal methylene groups
Methyltriphenoxyphosphonium Iodide (MTPI); Induced Dehydration and Dehydrohalogenation in Aprotic Solvents
Spangler, Charles W.,Kjell, Douglas P.,Wellander, Lori L.,Kinsella, Mary A.
, p. 2287 - 2289 (2007/10/02)
Methyltriphenoxyphosphonium iodide (MTPI) is an effective dehydration and dehydrohalogenation reagent under mild conditions when 1,3-dimethylimidazolidin-2-one is used as an aprotic solvent in place of the more normally used hexamethylphosphoric triamide (HMPT).Since previosly suggested mechanisms had proposed alcohol-HMPT interaction as an important mechanistic step, this result coupled with comparative product geometric isomer distributions and the conjugated: non-conjugated triene product ratios leads to the conclusion that MTPI-alcohol interaction with displacement of phenoxide is the primary step in the reaction.In dimethyl sulphoxide (DMSO) alcohol dehydratation is hindered by DMSO-MTPI interaction yielding dimethyl sulphide.
