1: bis-diphenylphosphine With n-butyllithium in hexane; toluene T=20°C; 0.5 h; Inert atmosphere; 2: 7-methyl--3-methylen-1,6-octadiene in hexane; toluene T=20°C; 4 h; Inert atmosphere; 3: With sulfur in hexane; toluene T=20°C; 3 h; Inert atmosphere; regioselective reaction;