“…The crystals were isolated from CHCl 3 at −20 • C, displaying the structure of (2) as already published in the literature. 4 The addition of acetone to compound (2) leads to high yields of a mixture of (1a,Z)/(1b,E) ( Figure 1). 31 P-NMR studies showed that the relative integrals between (1a,Z) and (1b,E) were found to be approx.…”