Premium
Mechanistic Aspects of Olefin Metathesis
Author(s) -
Calderon N.,
Ofstead E. A.,
Judy W. A.
Publication year - 1976
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.197604011
Subject(s) - metallacycle , metathesis , steric effects , carbene , olefin metathesis , acyclic diene metathesis , chemistry , stereochemistry , catalysis , organic chemistry , physics , polymerization , polymer , x ray crystallography , diffraction , optics
Abstract In this paper views regarding the nature of the transition state in olefin metathesis are discussed. Earlier concepts that assumed a pairwise scrambling mechanism have been recently challenged. Metathesis studies involving acyclic as well as cyclic olefins have been reported which strongly suggest a chain process that may involve a carbene‐to‐metallocycle interconversion as the pathway responsible for transalkylidenation. Catalytic systems that display a low apparent metathesis activity on terminal olefins display a unique specificity in cross reactions with internal olefins. Critical experiments indicate that terminal olefins rapidly undergo regenerative metathesis preferentially. Results suggest that in the transient metallocycle, the most stringent steric requirements occur at the β‐carbon, although the origin of this steric demand is not obvious.