in methanol T=0 - 5°C; Dimerization; methylthiodediazoniation;

n-butyllithium; potassium tert-butylate 1) hexane, a) -60 to -20 deg C, b) -20 deg C, 1 h, c) -10 deg C, 3 h, 2) r.t., overnight; Yield given. Multistep reaction;