Structural Studies on α-Pyrone Cycloadducts. Manifestation of the Early Stages of CO2 Extrusion by retro Hetero-Diels–Alder Reaction
Jesse Roth-Barton A , Yit Wooi Goh A , Asimo Karnezis A and Jonathan M. White A BA School of Chemistry and Bio-21 Institute, University of Melbourne, Vic. 3010, Australia.
B Corresponding author. Email: whitejm@unimelb.edu.au
Australian Journal of Chemistry 62(5) 407-412 https://doi.org/10.1071/CH09018
Submitted: 9 January 2009 Accepted: 20 March 2009 Published: 15 May 2009
Abstract
Structures of the α-pyrone (pyran-2-one) cycloadducts 4–8 show deviations of some bond distances from their normal values, consistent with manifestation of the early stages of the retro hetero-Diels–Alder decarboxylation reaction in the ground state structures. Thus the bridgehead C–O(CO) and C–CO(O) bonds are lengthened and the bridging C–O bond is shortened. The degree of lengthening of the C–O(CO) and C–CO(O) bonds is similar, whereas in the calculated transition state structure there is significant asymmetry in the extent of C–CO(O) and C–O(CO) bond breaking.
Acknowledgements
Our gratitude goes to the University of Melbourne for MIRS and MIFRS scholarships, and an Albert Shimmin Fund award to Goh Yit Wooi, and to the Australian Research Council for the award of an APRA to Asimo Karnezis.
[1]
K. Afarinkia,
V. Vinader,
T. D. Nelson,
G. H. Posner,
Tetrahedron 1992, 48, 9111.
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |
| Crossref | GoogleScholarGoogle Scholar |