... First page preview Click to open first page preview. Open this preview in PDF. Download full text in PDF. Tetrahedron Letters No. 25, pp. 44-47, 1960. Pergamon Fress Ltd. ... 4 E. Sp~th and N. Platzer, ibid. 69, 255 (1936). s p. L. Southwick and J. Casanova, Jr., J. Am. Chem. Soc. ...