M. Banwell et al., Chemoenzymatic approaches to the decahydro-as-indacene cores associated with the spinosyn class of insecticide, J CHEM S P1, (21), 2000, pp. 3555-3558
The enantiopure dienes 8 and 24, which have been prepared by chemoenzymatic
methods, engage in Diels-Alder cycloaddition reactions with maleic and cit
raconic anhydride to give adducts (e.g. 25-27) embodying the ABC-ring syste
m associated with spinosyns A (1) and D (2).