Study of the regioselectivity of addition of Grignard reagents onto imide ester 7 led to the expected phenyl derivative 12. By contrast, the methyl derivative 15 necessitated the use of a Mannich reaction onto the ketone 4. Finally, reaction of diethyl malonate with ketone 4 exhibited a dehydrogenation leading to a conjugate diester 19 and the expected diester 18.