1: 2-methyl-1-butene-3-yne With n-butyllithium; potassium tert-butylate in tetrahydrofuran; hexane T=-78 - 5°C; 0.666667 h; 2: 4-bromo-but-1-ene With lithium bromide in tetrahydrofuran; hexane T=-70 - -10°C;

maleic anhydride; dpca in tetrahydrofuran 50°C, 24 h;