boron trifluoride diethyl etherate T=-78 - -10°C; 1 h;

1: ethyl-1,4-pentadien-3-yl carbonate With titanium(IV) isopropylate; isopropylmagnesium chloride in diethyl ether T=-50 - -40°C; 2 h; 2: (E)-cinnamaldehyde in diethyl ether T=-40 - 0°C; 1 h; Title compound not separated from byproducts;