We are grateful to the National Science Foundation for financial support of this research (CHE-0548209, CHE-0450638, and CHE-0131944). Calculations were performed on the National Science Foundation Terascale Computing System at the NCSA and on the UCLA ATS Cluster. P.H.-Y.C. is grateful for discussions with the new-reactions subgroup of the Wender labs.
Substituent Effects, Reactant Preorganization, and Ligand Exchange Control the Reactivity in RhI-Catalyzed (5+2) Cycloadditions between Vinylcyclopropanes and Alkynes†
Article first published online: 15 APR 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Angewandte Chemie International Edition
Volume 47, Issue 21, pages 3939–3941, May 13, 2008
How to Cite
Liu, P., Cheong, P.-Y., Yu, Z.-X., Wender, Paul A. and Houk, Kendall N. (2008), Substituent Effects, Reactant Preorganization, and Ligand Exchange Control the Reactivity in RhI-Catalyzed (5+2) Cycloadditions between Vinylcyclopropanes and Alkynes. Angew. Chem. Int. Ed., 47: 3939–3941. doi: 10.1002/anie.200800420
- Issue published online: 6 MAY 2008
- Article first published online: 15 APR 2008
- Manuscript Received: 27 JAN 2008
- National Science Foundation. Grant Numbers: CHE-0548209, CHE-0450638, CHE-0131944
- density functional calculations;
Heteroatom and bulky alkyl substituents dramatically increase the rate of RhI-catalyzed (5+2) cycloadditions of 1. This fact could be attributed to steric effects which ease the reactant preorganization, and to the stabilization of the allyl intermediate by (hyper)conjugation with the substituents. The methoxy- and isopropyl-substituted 1 have an activation energy 5 and 7 kcal mol−1, respectively, lower than the unsubstituted vinylcyclopropane.