Small-ring Compounds. XX. 1,3-Dimethylenecyclobutane and Related Compounds¹

Abstract

1,3-Dimethylenecyclobutane and 1-methyl-3-methylenecyclobutene have been synthesized by way of 3-methylenecyclobutanecarboxylic acid and (3-methylenecyclobutylcarbinyl)-dimethylamine. No clear experimental evidence was obtained for π-type electronic interaction across the ring of 1,3-dimethylenecyclobutane.