A general method based on the sequential reactivities of bis-bromocycloalkenes (3–5) is proposed for the preparation of phosphonocycloalkanes (1a/b–3a/b), representing structural constrained analogues of AP4. For the synthesis of an additional congested AP4 analogue (4), an intramolecular cyclopropanation of a ketocarbene towards a vinyphoshonate, assisted by Rh (OAc) 2 was successfully experimented.
[Pinto Gomes, Cristiano; Metz, Alexander; Bats, Jan W.; Gohlke, Holger; Goebel, Michael W. European Journal of Organic Chemistry, 2012 , # 17 p. 3270 - 3277]