Regioselectivity in formal [3+2] cycloaddition reaction of 5-alkoxyoxazoles with diethyl oxomalonate and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

Citation
H. Suga et al., Regioselectivity in formal [3+2] cycloaddition reaction of 5-alkoxyoxazoles with diethyl oxomalonate and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, HETEROCYCLE, 55(9), 2001, pp. 1711
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
HETEROCYCLES
ISSN journal
0385-5414 → ACNP
Volume
55
Issue
9
Year of publication
2001
Database
ISI
SICI code
0385-5414(20010901)55:9<1711:RIF[CR>2.0.ZU;2-U
Abstract
Tin(IV) chloride-catalyzed formal [3 + 2] cycloaddition of 5-alkoxy-2-(p-me thoxyphenyl)- or 2-phenyloxazoles with diethyl oxomalonate gave 4,5,5-tris( alkoxycarbonyl)-2-oxazolines in high regioselectivity. Under similar condit ions, 4-substituted 5-alkoxy-2-methyloxazoles showed a trend to shift the r egioselectivity in favor for 3-oxazolines rather than 2-oxazolines. Reactio n of 5-alkoxy-4-ethoxycarbonyloxazoles with 2,3-dichloro-5,6-dicyano-1,4-be nzoquinone proceeded only under high pressure to give 2-oxazolines exclusiv ely.