(untitled) - Cram, D J; Helgeson, R C; Peacock, S C; Kaplan, L J; Domeier, L A; Moreau, P; Koga, K; Mayer, J M; Chao, Y; Siegel, M G; Hoffman, D H; Sogah, G D. Y (J. Org. Chem., 1978)