Ring-Expansion of Bridgehead Aldehydes with 1-Adamantanecarbonyl Cation or Benzoyl Trifluoromethanesulfonate: A New Route to Bicyclic and Tricyclic 1,2-Diols - Takeuchi, Ken'ichi; Kitagawa, Itsuko; Akiyama, Fumio; Shibata, Tadashi; Kato, Midori; Okamoto, Kunio (Synthesis, 1987)