NotesFAQContact Us
Collection
Advanced
Search Tips
Peer reviewed Peer reviewed
Direct linkDirect link
ERIC Number: EJ920486
Record Type: Journal
Publication Date: 2010-Nov
Pages: 4
Abstractor: As Provided
Reference Count: 17
ISBN: N/A
ISSN: ISSN-0021-9584
Using NMR to Probe the Regio- and Stereochemistry of the Hydration of 1-Hexene
Saba, Shahrokh; Clarke, Donald D.; Iwanoski, Christa; Lobasso, Thomas
Journal of Chemical Education, v87 n11 p1238-1241 Nov 2010
This undergraduate organic laboratory experiment complements previously described and popular experiments on hydration of 1-hexene where students experimentally establish the Markovnikov regioselectivity of alkene hydration. In this experiment, students explore not only the regiochemistry but also the stereochemistry of 1-hexene hydration and obtain spectral evidence that hydration of 1-hexene yields 2- and 3-hexanols as major products and that these chiral alcohols are obtained as racemic mixtures. This objective is achieved by converting commercial samples of racemic 2- and 3-hexanols to diastereomeric camphorsulfonate esters using commercial samples of enantiomerically pure (1"S")-(+)-10-camphorsulfonyl chloride. The product directly obtained from hydration of 1-hexene is also esterified using the same reagent. [superscript 1]H and [superscript 13]C NMR spectra of the products from each reaction are then obtained, analyzed, and compared. Thus, students determine the composition of the diastereomeric mixtures. The results lead to a postlab discussion of NMR spectroscopic analysis of enantiomers and diastereomers, stereochemical relationships between faces of planar species such as carbocations, and the effect of a chiral auxiliary on a racemate. Most importantly, students experimentally prove one of the main doctrines of organic stereochemistry whereby racemates are always produced from reactions of achiral starting materials that afford chiral products. (Contains 4 notes, 3 figures and 2 schemes.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A