Williams DR, Reeves JT, Nag PP, Pitcock WH, Baik M-H. Studies of the generation and pericyclic behavior of cyclic pentadienyl carbanions. Alkylation reactions as an efficient route to functionalized cis-bicyclo[3.3.0]octenes. J Am Chem Soc. 2006;128(37):12339-48. doi:10.1021/ja063243l.