1: ethylmagnesium bromide; cis-2,10-dimethyl-lt;1,2,3gt;benzothiadiphosphololt;2,3-bgt;lt;1,2,3gt;benzothiadiphosphole; Bromure de phenyl magnesium in tetrahydrofuran 0.0833333 h; 2: methylmagnesium bromide in tetrahydrofuran 3: With sulfur in tetrahydrofuran

in diethyl ether

in diethyl ether

(i), (ii) (thermolysis); Multistep reaction;