... Tetrahedron, 33 (1977), pp. 1291–1302. ... 10; KA Lukin, NS Zefirov; Zh. Org. Khim., 23 (1987), pp. 2548–2552. 11; 1 H NMR of a crude product indicated ∼ 10% of admixture that was tentatively assigned structure of 2-bromo-1-[(1-bromo-2-methylenecyclobutyl)methyl]cyclobutene. However, this compound decomposed during attempted isolation by distillation or column chromatography. ...