Synthesis of Cis,syndiotactic A-alt-B Copolymers from Two Enantiomerically Pure Trans-2,3-Disubstituted-5,6-Norbornenes

Cis, syndiotactic A-alt-B copolymers, where A and B are two enantiomerically pure trans-2,3-disubstituted- 5,6-norbornenes with "opposite" chiralities, can be prepared with stereogenic-at-metal initiators of the type M(NR)- (CHR')(OR")(pyrrolide). Formation of a high percentage o...

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Bibliographic Details
Main Authors: Jang, Eun Sil, John, Jeremy M, Schrock, Richard Royce
Other Authors: Massachusetts Institute of Technology. Department of Chemistry
Format: Article
Published: American Chemical Society (ACS) 2018
Online Access:http://hdl.handle.net/1721.1/113613
https://orcid.org/0000-0002-7405-6811
https://orcid.org/0000-0001-5827-3552
Description
Summary:Cis, syndiotactic A-alt-B copolymers, where A and B are two enantiomerically pure trans-2,3-disubstituted- 5,6-norbornenes with "opposite" chiralities, can be prepared with stereogenic-at-metal initiators of the type M(NR)- (CHR')(OR")(pyrrolide). Formation of a high percentage of alternating AB copolymer linkages relies on an inversion of chirality at the metal with each propagating step and a relatively fast formation of an AB sequence as a consequence of a preferred diastereomeric relationship between the chirality at the metal and the chirality of the monomer. This approach to formation of an alternating AB copolymer contrasts dramatically with the principle of forming AB copolymers from achiral monomers and catalysts.