A general method is described to convert the title compound into more compl
ex nitrogen heterocyclic systems in a short and attractive pathway. Spirois
oxazolidine 6 was obtained from the reaction of nitrone 3 with ethyl vinyl
ether. Chloroformylation of pyrrolone 2 gave 1-aryl-2-chloro-5-methoxy-pyrr
ol-3-carbaldehyde 4. Substitution of chlorine atom with unsaturated nucleop
hiles 8a,b and then modifying the aldehyde function into 1,3-dipoles 10 and
14 furnished tricyclic heterocycles 11, 12 and 15 via intramolecular 1,3-d
ipolar cycloaddition reaction. (C) 2000 Elsevier Science Ltd. All rights re
served.