in chloroform-d1 T=20°C; 0.0833333 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;