" All reactions were performed under the standard conditions reported in the text unless otherwise noted. bE= C02CH3.< This reaction was performed in THF alone. dThe GC shows only one peak for the diene. The NMR spectrum shows predominantly one isomer but a small doublet at 6 1.6 may correspond to a minor amount of the geometrical isomer. CThe GC shows only one peak. Too little of the minor product is present to allow an accurate ...