Ba. Marples et Cd. Spilling, THE INTRAMOLECULAR ENE REACTION OF (PROP-2-ENYL)-2-XI-HYDROXY-5-ALPHA-CHOLESTAN-3-ONE, Tetrahedron, 50(47), 1994, pp. 13461-13468
The title unsaturated acyloin undergoes the relatively low temperature
(110 degrees C) intramolecular ene reaction to give the 2,5-ethano-ac
yloin (17) which rearranges to the 3,5-ethano-isomer (16).