1. (a) Reviews: Bailey, W. F.; Ovaska, T. V. InAdvances in DetailedReaction Mechanisms; Coxon, J. M., Ed.; JAI Press: Greenwich, CT.; Vol. 3, 1994; p 251−273. Mealy, M. J.; Bailey, W. F.J. Organomet. Chem.2002,646, 59−67. Clayden, J.Organolithiums: Selectivity for Synthesis;Pergamon Press: New York, 2002; pp 293−335. The earliest reports of such cyclizations involved Grignard reagents and are due to the pioneering work of Richey: (b) Richey, H. G., Jr.; Rees, T. C.Tetrahedron Lett.1966,36, 4297−4301. Kossa, W. C., Jr.; Rees, T. C.; Richey, H. G., Jr.TetrahedronLett.1971, 3455−3458.
2. The only other examples of intramolecular carbolithiation of nonconjugated alkyllithiums prepared by reductive lithiation are by (a) Broka, C. A.; Shen, T.J. Am. Chem. Soc.1989, 111, 2981−84, in which phenyl thioethers are substrates (two examples), (b) Rychnovsky, S. D.; Hata, T.; Kim, A. I.; Buckmelter, A. J.Org. Lett.2001,3, 807−810, in which a nitrile was the substrate (one example), and (c) Yus, M.; Ortiz, R.; Huerta, F. F.Tetrahedron Lett.2002,43, 2957−2960, in which an alkyl chloride was the substrate. In 3c, very special conditions were required for the tertiary case. References 3a and 3b appeared after we had completed much of our work described herein.
3. Preparation and regiospecific cyclization of alkenyllithiums