.write the mechanism for 9,10,11,12,,13,compounds

Reagents and conditions: (a) Red-Al (70% in toluene, 1.6 equiv), THF, -15 f 0 C, 24 h; then EtOAc (1.6 equiv), I2 (1.6 equiv), -78 f 23 C, 1 h, 87%; (b) trimethylsilyl acetylene (1.5 equiv), Pd(PPh3)4 (0.05 equiv), CuI (0.2 equiv), Et3N/i-Pr2NEt (2:1), 23 C, 30 min, 92%; (c) K2CO3 (3.0 equiv), MeOH, 23 C, 30 min, 97%; (d) Ph3PAuCl (0.02 equiv), AgOTf (0.02 equiv), THF, 23 C, 1 h, 91%; (e) POCl3 (1.5 equiv), DMF, 0 f 23 C, 1 h, 88%

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