... Tetrahedron. Volume 43, Issue 21, 1987, Pages 5031-5038. Cover image. ... The mechanism of this ring expansion process has been discussed. Download full text in PDF. Tetrahedron Vol 43, No 21. pp 5031 to 5038, 1987 0040-4020/87 .00+ 00 Printed in Great Bnlain. ...