Retention and Selectivity of Teicoplanin Stationary Phases after Copper Complexation and Isotopic Exchange
作者:Alain Berthod、Alain Valleix、Veronique Tizon、Estelle Leonce、Celine Caussignac、Daniel W. Armstrong
DOI:10.1021/ac010444t
日期:2001.11.1
Teicoplanin is a macrocyclic glycopeptide that is highly effective as a chiralselector for LC enantiomeric separations. Two possible interaction paths were investigated and related to solute retention and selectivity: (1) interactions with the only teicoplanin amine group and (2) role of hydrogen bonding interactions. Mobile phases containing 0.5 and 5 mM copper ions were used to try to block the
homologation of unstrained aryl ketones through a formal 1,1-insertion process of olefins, enabled by temporary directing group (TDG)-aided C–C activation. The reaction provides a distinct approach to access various substituted 1-indanones. Computational mechanistic studies reveal that the formal 1,1-insertion is realized by a selective C(sp2)–C(sp3) activation and turnover limiting 2,1-insertion into
Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts
申请人:——
公开号:US20010021755A1
公开(公告)日:2001-09-13
Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts.
A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluninoxane or a supported aluminoxane, and a metallocene of the formula I
1
in which, in the preferred form, M
1
is Zr or Ef, R
1
and R
2
are halogen or alkyl, R
3
is alkyl, R
4
to R
12
are alkyl or hydrogen and R
13
is a (substituted) alkylene or heteroatom bridge.
The metallocenes, in particular the zirconocenes, produce polymers of very high molecular weight, in the case of prochiral monomers polymers of very high molecular weight, very high stereotacticity and very high melting point, at high catalyst activities in the industrially particularly interesting temperature range between 50 and 80° C. In addition, reactor deposits are avoided by means of supported catalyst systems.
A process for the preparation of indanones of the formula II from indanones of the formula I or of indanones of the formula IIa from indanones of the formula Ia
1
comprises reacting an indanone of the formula I or Ia with a coupling component.
Metallocenes containing aryl-substituted indenyl derivatives as ligands,
申请人:Targor GmbH
公开号:US05770753A1
公开(公告)日:1998-06-23
Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts. A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluminoxane or a supported aluminoxane, and a metallocene of the formula I ##STR1## in which, in the preferred form, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are halogen or alkyl, R.sup.3 is alkyl, R.sup.4 to R.sup.12 are alkyl or hydrogen and R.sup.13 is a (substituted) alkylene or heteroatom bridge. The metallocenes, in particular the zirconocenes, produce polymers of very high molecular weight, in the case of prochiral monomers polymers of very high molecular weight, very high stereotacticity and very high melting point, at high catalyst activities in the industrially particularly interesting temperature range between 50.degree. and 80.degree. C. In addition, reactor deposits are avoided by means of supported catalyst systems.