Stereospecific Synthesis of the Geometrical Isomers of a Natural Product
-
T. Grove [1] ; D. DiLella [1]
-
[1] Shepherd University
Shepherd University
Estados Unidos
-
- Localización: Journal of chemical education, ISSN 0021-9584, Vol. 83, Nº 7, 2006, pág. 1055
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
-
Resumen
Stereospecific synthesis of a geometrical isomer is not a common topic for the introductory organic chemistry laboratory. We have developed and tested an experiment for the synthesis of (Z) and (E) isomers that has been performed successfully by undergraduate students. The experiment is presented to the students as a puzzle in which they must determine the identity of the major component in anise oil. A necessary part of the analysis is the preparation the (E) and (Z) isomers of anethole. The Suzuki reaction of Pd(0)-catalyzed coupling between an aryl boronic acid and a vinyl halide is selected for these syntheses. Students typically synthesize the desired product with 95% selectivity. No special equipment is required and the products can be readily analyzed with GC–MS, NMR, and IR. Molecular modeling is used to explore the conformation of and the energy difference between the isomers. Several variations and extensions to the basic experiment are also described.
