1: 2,4-dimethylpentan-3-one With lithium diisopropyl amide in tetrahydrofuran; n-heptane T=0°C; 1 h; 2: benzyl bromide in tetrahydrofuran; n-heptane T=0 - 50°C;

1: 3,3-dimethyl-2-methylene-4-phenyloxetane With 4,4'-di-tert-butylbiphenyl; lithium in tetrahydrofuran T=20°C; Ring cleavage; reduction; 2 h; 2: methyl iodide in tetrahydrofuran T=-78°C; Methylation; 1 h;

sulfuric acid; acetic acid