instead of Cl), but we were unable to convert it into the required 5a under a variety of conditions. Product 5a presented a crystalline form not suitable for the X-ray single-crystal structure determination we needed in order to determinate double bond geometry and molecular shape. Accordingly, the above analysis was performed on the methyl ester 6, mp 142 OC, prepared from 5a upon treatment with ethereal diazomethane. Figure 1, showing ...
