Norbomene chiral substituents

Metathesis catalysts with one chiral A-substituent (e.g., 17) are useful for ROMP. In alternating copolymerization of norbomene with other cycloalkenes the steric interactions of the growing polymer chain dictate selectivity. 

Tacticities have been determined for polymers of various derivatives of norbomene, norbomadiene and 7-oxanorbomene. Three methods have been used (i) by polymerizing single enantiomers of 5-, or 5,5-, or e rfo,exo-5,6-disubstituted derivatives, and determining whether the polymers have an HT (m) or HH/TT (r) stmcture, or both (m and r) (ii) by polymerizing 5,6-disubstituted derivatives in which the substituents contain a chiral centre of a single handedness, and... 

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