New ring expansion of cyclobutanones: Synthesis of pyrrolinones, pyrrolidines and pyrroles

…, S Boterberg, F Bombeke, CV Stevens, N De Kimpe

Index: Verniest, Guido; Boterberg, Stefaan; Bombeke, Filip; Stevens, Christian V.; De Kimpe, Norbert Synlett, 2004 , # 6 p. 1059 - 1063

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Citation Number: 10

Abstract

Both 2,2-dibromocyclobutanones and 2,2-dichlorocyclobutanones were synthesized in order to compare their ability for ring expansion towards 3-pyrrolinones. The synthesis of these small ring compounds involves a [2+2]-cycloaddition of in situ generated dihalogenated ketenes to substituted styrenes. [12] [13] In contrast to the synthesis of 2,2-dibromocyclobutanone, which is a more laborious and low yielding procedure, 2,2-dichlorocyclobutanones are readily ...