(i) Mg, FeCl3, EtBr, THF, (ii) /BRN= 1900390/; Multistep reaction;

1: 7-methyl--3-methylen-1,6-octadiene; isopropylmagnesium chloride With [NiCl2Py4] in tetrahydrofuran T=20°C; Grignard reaction; 2: carbon dioxide in tetrahydrofuran Title compound not separated from byproducts;