S. Bailey et al., TOTAL SYNTHESIS OF MILBEMYCIN-G - ASSEMBLY AND COMPLETION OF THE SYNTHESIS, Journal of the Chemical Society, Chemical Communications, (24), 1995, pp. 2521-2522
The Wittig reaction between phosphonium salt 1 and the hydroxybutenoli
de 2 followed by deprotection, macrocyclisation, and reduction gives t
he 6-hydroxymilbemycin E 9 which by further cyclisation is converted i
nto milbemycin G 11.