The infrared spectrum of the product showed the characteristic y-lactone carbonyl band at 5.65 pM. The stereochemical configuration of the lactone ring 2a was subsequently established as cis by X-ray crystallographic structure determination (Figure 1). Several attempts to vary the reaction time and temperature of this inverse Grignard reaction resulted in an optimum yield of only 25% due to competitive reaction with the ester. Catalytic ...
[Kees, Kenneth L.; Caggiano, Thomas J.; Steiner, Kurt E.; Fitzgerald, John J.; Kates, Michael J.; et al. Journal of Medicinal Chemistry, 1995 , vol. 38, # 4 p. 617 - 628]
