Scheme 7.
Synthesis of 8a and 8b.a
aReagents: (i) DBU (1.1 equiv), benzene, rt, 2 h; (ii) H2O2 (30%) (5 equiv), NaOH (1M in H2O), MeOH, 20 min.
Synthesis of 8a and 8b.a
aReagents: (i) DBU (1.1 equiv), benzene, rt, 2 h; (ii) H2O2 (30%) (5 equiv), NaOH (1M in H2O), MeOH, 20 min.