1: With Cp2ZrEt2 metallo-esterification; 2: With hydrogenchloride T=20°C; Hydrolysis; 1 h;

1: With titanium(IV) isopropylate; cyclopentyl-magnesium chloride in diethyl ether T=0°C; Inert atmosphere; 2: With hydrogenchloride; water in diethyl ether T=0°C; Inert atmosphere; diastereoselective reaction;

in tetrahydrofuran T=20°C; Yield given. Yields of byproduct given. Title compound not separated from byproducts;