The efficiency of the ruthenium-catalysed Alder-ene reaction of hydroxy alkenes depends heavily on the nature of the O-protecting groups employed as well as the length of the carbon spacer between the hydroxy and alkene group.
History
Citation
Hartley, J. & Pyne, S. G. (2004). Protecting group effects on the efficiency of the ruthenium-catalyzed Alder-ene reaction. Synlett: accounts and rapid communications in synthetic organic chemistry, 12 2209-2211.