... ' '5) a) MC Wani, HF Campbell, GA Brine,'J.A_.'Kepler, and ME. Wall, J. Am. Chem. Soc., 94, 3632 (1972); b) L]. Plattner, RD Glass, and H. Rapoport, ibid., 94, 8613 (1972); c) T. Sugasawa, T. ' Toyoda, and K. Sasakura, Tetrahedron Letters, 1972, 5109. . 6) 01) RH. ...