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Type of Document	Dissertation
Author	Byers, Jeffery Allen
URN	etd-05162007-152948
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-05162007-152948
Title	Synthetic and mechanistic studies into the kinetic resolution of alpha-olefins using C1- and C2- symmetric zirconocene polymerization catalysts
Degree	PhD
Option	Chemistry
Advisory Committee	Advisor Name Title Brian M. Stoltz Committee Chair John E. Bercaw Committee Member Jonas C. Peters Committee Member Robert H. Grubbs Committee Member
Keywords	13C labeled olefin asymmetric catalysis swivel frit
Date of Defense	2007-05-24
Availability	unrestricted
Abstract Mechanistic and synthetic investigations into the kinetic resolution of racemic alpha-olefins by polymerization catalysis using C1- and C2-symmetric zirconocenes are reported. The importance of chain end control as a stereocontrol element was probed with ethylene and propylene copolymerizations catalyzed by the C1-symmetric catalyst, {1,2-(SiMe2)2(eta-5-3,5-C5H1(CHMe2)2)(eta-5-4-C5H2((S)-CHMeCMe3)]}ZrCl2/MAO. Selectivity factors and pentad analysis of racemic alpha-olefin and propylene polymerizations catalyzed by a similar C1-symmetric catalyst, {1,2-(SiMe2)2(eta-5-3,5-C5H1(CHMe2)2)(eta-5-4-C5H2((S)-CHEtCMe3)]}ZrCl2/MAO, indicate that site epimerization does not limit selectivity during kinetic resolution. To avoid some of the issues involved with the C1-symmetric catalysts, a route to enantiopure C2-symmetric zirconocenes was pursued. With the aid of the chiral auxiliary, (R)-N2,N2’-di-p-tolyl-1,1’-binaphtyl-2,2’-diamine, enantiospecefic synthesis of (S,S)-{C2H4-1,2-(1-indene)2}ZrCl2 was accomplished and its use for kinetic resolution was investigated. Although synthetically useful selectivities were not observed, it was determined that the C2-symmetric catalyst does not racemize during polymerization, which substantiates a more thorough investigation of catalysts based on {C2H4-1,2-(1-indene)2}ZrCl2.
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