(1) ME Herr and FW Heyl, THIS JOURNAL, 76, 5928 (1953). Alternative methods of preparation have been reported by 0. Mancera, G. Rosenkranz and F. Sondheimer, J. Ckcm. SOC., 2189 (1953); S. Bernstein, RH Lenhard and GH Williams, J. Org. Chcm., 18, I166 (1953).(2)(a) CW Shoppee and T. Reichstein, Hclw. Chim. Acto, 24, 351 (1941); 26, 1316 (1943);(b) H. Heymann and LF Fieser, THIS JOURNAL, 74, 5939 (1952).
