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Dynamic isotope dilution kinetic study of the thermal conversions of bicyclo[3.2.0]hept‐2‐ene to bicyclo[2.2.1]hept‐2‐ene and to cyclopentadiene and ethene
Author(s) -
Baldwin John E.,
Belfield Kevin D.
Publication year - 1989
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610020604
Subject(s) - bicyclic molecule , ene reaction , chemistry , cyclopentadiene , octene , kinetic isotope effect , stereochemistry , deuterium , organic chemistry , ethylene , catalysis , physics , quantum mechanics
Mixtures of bicyclo[3.2.0]hept‐2‐ene and bicyclo[2.2.1]hept‐2‐ene, with one isomer labeled with two deuterium atoms, were isomerized in the gas phase at 276 °C. By following the concentration ratios of d 0 and d 2 versions of bicyclo[2.2.1]hept‐2‐ene as functions of time one finds that the partitioning of bicyclo[3.2.0]hept‐2‐ene between the primary products bicyclo[2.2.1]hept‐2‐ene and cyclopentadiene plus ethene is 2:1. This and earlier stereochemical results permit the calculation of the partitioning of the [3.2.0] olefin between the orbital symmetry allowed [1,3] carbon shift‐with‐inversion product and several forbidden or non‐concerted reaction channels (approximately 1:1) and the stereochemistry of the ethene d 2 formed from exo , exo ‐[6,7‐ 2 H 2 ]bicyclo[3.2.0]hept‐2‐ene directly (1:1 E : Z ).