1: methyllithium With cerium(III) chloride in tetrahydrofuran T=-78°C; 0.5 h; Inert atmosphere; 2: 1-benzyl-5-methylsulfanyl-3,4-dihydro-2H-pyrrolium iodide in tetrahydrofuran T=-78°C;

in tetrahydrofuran 6 h; Inert atmosphereSonication;