Carbonium vs. carbenium ion-like transition state geometries for carbocation cyclization - how strain associated with bridging affects 5- exo vs. 6- endo selectivity.

Autor: Gutierrez O; Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA., Harrison JG; Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA., Felix RJ; Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina 27599-3190, USA., Guzman FC; Instituto de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico., Gagné MR; Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina 27599-3190, USA., Tantillo DJ; Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA.
Jazyk: angličtina
Zdroj: Chemical science [Chem Sci] 2013 Oct; Vol. 4 (10).
DOI: 10.1039/C3SC51657A
Abstrakt: Quantum chemical calculations are used to explore the origins of regioselectivity for proton-, Pt(II)- and Pd(II)-promoted cyclizations of 1,5-hexadienes, 5-aminoalkenes, and allylic acetimidates. The strain associated with achieving carbonium ion-like transition state geometries is shown to be a key factor in controlling 5- exo vs. 6- endo selectivity.
Databáze: MEDLINE