... Chem. Sot. 74.441 (1952) ' F. Weygand. KG Kinkcl and D. Tictjen. C/tern. Ber. 85,394 (1950) ' J. Altman. E Babad, J. Pucknat, N. Rahef and D. Ginsburg, Tetrahedron 24,975 (1968) and unpublished observations in this laboratory. Page 8. 100 J. AMMAN and D. GINSBURG 6 0. Sciacovclli W. van Philipsbom. C. Amitb and D. Ginsburg, Ibid. 26.4589 (1970) ' GN Schrauzcr. P. Glockna and R. Matnyi, Angew. Chem. 76,498 (1964) * U. Krilcrkc. Ibid. intern. ...