Scheme 1. Syntheses of aulosirazole, pronqodine Aand various analogues. Reagents and conditions:a)nBuLi, Et2O, hexanes, ¢258 8C, 18 h; dimethyl disulfide, THF, RT,4.5 h, 50%; b) conc. HCl, THF, RT,1.5 h, 82%; c) NH2OH·HCl, NaOH, EtOH, H2O, RT,20h,79%;d)sulfuryl chloride, PhCl, RT,808 8C, 1h;dimethyl sulfate, K2CO3,DMF, RT,16h,18%;e)Br 2,AcOH, RT,1.5 h, 49%; f)CAN, H2O, MeCN, RT,1h, 59%; g) CAN, H2O, MeCN, RT,45h,61%;(h) pyrone 8,NEt3,CHCl3,R T, 40 min, 13%; i) pyrone 8,NEt3,CHCl3,R T, 15 min, 50%; j) conc. HCl, THF, RT,1.5 h, 82%; k) NH2OH·HCl, formic acid, 1008 8C, 1.5 h, 63%; l) Br2,CHCl3,R T, 3h,66%;m)CAN, H2O, MeCN, RT,1h, 59%; n) CAN, H2O, MeCN, RT,1h, 82%; o) pyrone 8,NEt3,CH 2Cl2,R T, 14 h, 30%; p) pyrone 8,NEt3,CHCl3,R T, 30 min, 30%; q) MeNH2,CeCl3·7H2O, EtOH, RT, 1h,42%;r)benzylamine, CeCl3·7H2O, EtOH, RT,30min, 38%; s) pyrrolidine, CeCl3·7H2O, EtOH, RT,30min, 60%. CAN=cerium(IV) ammonium nitrate.