16939-16-5

Upstream product

• 1095419-50-3 3-phenylpent-2-ene 
• 30319-05-2 3-bromo-2-methylthiophene 
• 1565-71-5 3-phenylpentan-3-ol 
• 100-58-3 phenylmagnesium bromide 
• 31254-19-0 1-Ethyl-1-phenylallyl alcohol 

Downstream Products

• 345306-44-7 (2,5-Me₂-3-Ph-6-hydrocyclopenta[2,3-b]thiophen-6-yl)2SiMe₂ 

Relevant academic research and scientific papers

Redox-Divergent Construction of (Dihydro)thiophenes with DMSO

Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.

Polycyclic fused heteroring compounds metal complexes and polymerization process

Metal complexes comprising a polycyclic, heteroatom containing fused ring compound comprising at least a cyclopentadienyl ring having fused thereto a 5-membered polyatomic ring containing one or more ring atoms selected from groups 15 or 16 of the Periodic Table of the Elements and lacking substituents forming 6-membered, aromatic fused rings; polymerization catalysts; and olefin polymerization processes using the same are disclosed.

Metallocene compounds, process for their preparation and their use in catalytic systems for the polymerization of olefins

A class of metallocene compounds is disclosed having the general formula (I): wherein Y is a moiety of formula (II) wherein A, B and D, same or different from each other, are selected from an element of the groups 14 to 16 of the Periodic Table of the Elements (new IUPAC version), with the exclusion of nitrogen and oxygen; R1, R2, R3, R4and R5are hydrogen or hydrocarbon groups, Z is selected from a moiety of formula (II) as described above and from a moiety of formula (III): wherein R6, R7, R8and R9, are hydrogen or hydrocarbon groups; L is a divalent bridging group; M is an atom of a transition metal selected from those belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table of the Elements (new IUPAC version), X, same or different, is hydrogen, a halogen, a R10, OR10, OSO2CF3, OCOR10, SR10, NR102or PR102group, wherein the substituents R10are hydrogen or alkyl groups; p is an integer of from 0 to 3, being equal to the oxidation state of the metal M minus 2. The above metallocenes are particular useful in the polymerization of propylene.

Chiral ansa metallocenes with Cp ring-fused to thiophenes and pyrroles: Syntheses, crystal structures, and isotactic polypropylene catalysts

Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) and pyrroles (Pyr) are reported. The C2and C1-symmetric heterocenes are dimethylsilyl bridged, have methyl groups adjacent to the bridgehead carbon atoms, and have aryl substituents protruding in the front. rac-Me2Si(2,5-Me2-3-Ph-6-Cp [b]Tp)2ZrCl2/MAO (MAO = methyl alumoxanes) is the most active metallocene catalyst for polypropylene reported to date. rac-Me2Si (2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 and rac-Me2Si (2,5-Me2-1-Ph-4-Cp[b]Pyr)2ZrCl2 have the same structure, and the former is 6 times more active, produces half the total enantiofacial errors, and is 3.5 times less regiospecific in propylene polymerizations at the same conditions. rac-Me2Si(2-Me-4-Ph-1-Ind)2ZrCl2/ MAO is 3.5 times lower in activity than rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b] Tp)2ZrCl2 catalyst, and while the former is the more stereospecific and the less regiospecific, the sum of these two enantioface errors is the same for both species. Fine-tuning the heterocene sterics by changing selected hydrogen atoms on the ligands to methyl groups influenced their catalyst activities, stereospecificites, regiospecificites, and isotactic polypropylene (IPP) Mw. Thus, both substituting a hydrogen atom adjacent to the phenyl ring with a methyl group on an azapentalenyl ligand system and replacing one and then two hydrogens on the phenyl ring with methyls on thiopentalenyl ligands provided increased polymer Tm and Mw with increasing ligand bulk. Polymer molecular weights are sensitive to and inversely proportional to MAO concentration, and the catalyst activities increase when hydrogen is added for molecular weight control. The polymer Tm values with the thiopentalenyls as TIBAL/[Ph3C][B(C6F5)4] systems were higher than with MAO as catalyst activator. A racemic C1, pseudomeso complex with a hybrid dimethylsilyl-bridged 2-Me-4-Ph-1 1-Ind/2,5-Me2-4-Ph-1-Cp[b]Pyr ligand produced the first sample of IPP with all the steric pentad intensities fitting the enantiomorphic site control model. Speculative mechanistic considerations are offered regarding electronic effects of the heteroatoms and steric effects of the ligand structures, the preferred phenyl torsion angles, and anion effects.