ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Formation of 4-, 5- and 6-membered heterocycles by ambidoselective cyclization of enolate anionsN-Acylmethyl-N-chloracetyl-2,6-dimethylanilines 4 were cyclized with base to 4-, 5- or 6-membered ring compounds, depending on the substituent R2 (Scheme 2). All products can be rationalized as derived from the intermediate enolate anions a and b. The enolate anion a reacts by intramolecular alkylation to yield either 1, 4-oxazines 5 or azetidines 6 (Schemes 1, 3 and 7). The regioselectivity observed is expected on the basis of the allopolarization principle. The enolate anion b reacts only with formation of a new C—C bond (Scheme 5). Comparison with the behaviour of the 2, 6-unsubstituted anilines 9, 1a and 12, shows a strong dependence not only on electronic but also on steric factors (Scheme 4 and 6).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19790620326
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