A solution of compound 3h (3.40 g, 10.11 mmol) and methyl acrylate (2.02 g, 23.46 mmol) in EtOH (abs., 5 mL) was stirred at RT for 28 hours. The volatile components were removed in vacuo and the product purified on a dry column (eluting from heptane, 10% EtOAc) and dried in vacuo to give 4.26 g (quant.) of the product as a colorless oil. 1