2-Methylenebutyrolactones. I. Monoaryl derivatives

Abstract

The Mannich reaction of a dialkylamine and formaldehyde with 2-carboxy- butyrolactones leads directly to isolable 2-methylenebutyrolactones. It is suggested that this happens through a concerted decarboxylation-elimination mechanism. 2-Methylene-3- and -4-phenylbutyrolactones and their cysteine addition products, and 3-methylene-2-oxo-cis-2,3,3a,4,5,9b-hexhydronaphtho[1,2-b]furan and its di-methylamine addition product have been prepared. 3-Oxo-2,3,4,4a,6,6-hexahydro-naphtho[l,2-c]pyridazine has also been synthesized.