1: (3aS,4S,6aR)-2,2-dimethyl-6-[(trityloxy)methyl]-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-ol With di-isopropyl azodicarboxylate; triphenylphosphine in tetrahydrofuran T=-78 - 0°C; Mitsunobu reaction; 1 h; 2: 4-(N6,N6-di-tert-butyloxycarbonylamino)-imidazo[4,5-c]pyridine in tetrahydrofuran T=-78 - 20°C; 48 h;

sodium hydrogencarbonate in tetrahydrofuran Product distribution / selectivity;