- Catalytic enantioselective desymmetrization of cyclobutane-1,3diones by carbonyl-amine condensation
-
A chiral phosphoric acid-catalyzed enantioselective condensation of 2,2-disubstituted cyclobutane-1,3-diones with a primary amine is described. This reaction offered a mild and efficient protocol for constructing quaternary carbon-containing cyclobutanes
- Wen, Kai-Ge,Liu, Chao,Wei, Dong-Hui,Niu, Yan-Fei,Peng, Yi-Yuan,Zeng, Xing-Ping
-
-
Read Online
- HALOGEN SUBSTITUTED METALLOCENE COMPOUNDS FOR OLEFIN POLYMERIZATION
-
A metallocene compound is represented by the formula (1): AMXn-1 wherein M is a transition metal atom having a coordination number of n selected from Group 3, 4, 5 or 6 of the Periodic Table of Elements, or a lanthanide metal atom, or actinide metal atom; A is a substituted monocyclic or polycyclic arenyl ligand pi-bonded to M, wherein said arenyl ligand includes at least one halogen substituent directly bonded to any sp2 carbon atom at a bondable ring position of the ligand; and the or each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand.
- -
-
Page/Page column 104-105
(2010/11/27)
-
- HALOGEN SUBSTITUTED METALLOCENE COMPOUNDS FOR OLEFIN POLYMERIZATION
-
A metallocene compound is represented by the formula (1): wherein: M is a Group 3, 4, 5 or 6 transition metal atom, or a lanthanide metal atom, or actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium or hafnium; E is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand pi-bonded to M; A is a substituted or unsubstituted polycyclic arenyl ligand that is pi-bonded to M and has a different ring structure than the E ligand; at least one of the A and E ligands includes at least one halogen substituent directly bonded to an sp2 carbon at a bondable ring position; Y is a bridging group containing at least one Group 13, 14, 15, or 16 element and any single position of the ring structure of A and to any single position of the ring structure of E; and y is zero or 1, indicating the absence (y = 0) or presence (y =1) of Y; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; provided that when E is an unsubstituted cyclopentadienyl ligand, either y is one or A is not 2-bromofluorenyl or 2,7-dibromofluorenyl.
- -
-
Page/Page column 95-96
(2010/11/27)
-