Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Stereoselective Isomerizations of 4-(2´-Chloro-3´-methoxyphenyl)-2,5-dimethyl-1,3-dioxolanes: Stereochemistry and Conformation of the Product 2-Benzopyrans

Giles, R.G.F., Green, I.R. and Li, S-H (2005) Stereoselective Isomerizations of 4-(2´-Chloro-3´-methoxyphenyl)-2,5-dimethyl-1,3-dioxolanes: Stereochemistry and Conformation of the Product 2-Benzopyrans. Australian Journal of Chemistry, 58 (8). pp. 565-571.

Link to Published Version: http://dx.doi.org/10.1071/CH05120
*Subscription may be required

Abstract

Stereoselective isomerization of rel-(2R,4S,5R)-4-(2′-chloro-3′-methoxyphenyl)-2,5-dimethyl-1, 3-dioxolane 5 with titanium(IV) chloride afforded solely rel-(1R,3R,4S)-5-chloro-4-hydroxy-6-methoxy-1,3-dimethyl-2-benzopyran 17 in high yield in which the conformation adopted by the dihydropyran ring minimized peri-interactions through stereochemistries that were axial for the C-3 methyl, pseudoaxial for the C-4 hydroxy and pseudoequatorial for the C-1 methyl groups. Similar isomerization of the individual rel-(2S,4R,5R)- and rel-(2R,4R,5R)-diastereoisomeric dioxolanes 6 and 7 gave solely the corresponding rel-(1S,3R,4R)-2-benzopyran 25 in which the orientations of the substituents at C-3, C-4 and C-1 were equatorial, pseudoaxial and pseudoequatorial respectively. These observations differed significantly from those previously made for the related isomerizations of the corresponding 4-(2′-chloro-5′-methoxyphenyl)-2,5-dimethyl-1,3-dioxolanes.

Item Type: Journal Article
Murdoch Affiliation: School of Chemical and Mathematical Science
Publisher: Commonwealth Scientific and Industrial Research Organization Publishing
Copyright: © CSIRO 2005
URI: http://researchrepository.murdoch.edu.au/id/eprint/15027
Item Control Page Item Control Page