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. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Angew Chem Int Ed Engl. 2009;48(32):5860–5863. doi: 10.1002/anie.200902509

Scheme 1.

Scheme 1

Construction of key buliding blocks bromo-aldehyde 6 and iodo-enone 7. Reagents and conditions: a) AlCl3 (1.2 equiv), CH2Cl2, 25 °C, 3 h, 80 %; b) PhI(CF3CO2)2 (3.0 equiv), MeCN, H2O, 25 °C, 30 min, 97 %; c) Na2S2O4 (5.0 equiv), EtOAc, H2O, 25 °C, 10 min; SEMCl (4.0 equiv), iPr2NEt (6.0 equiv), DMF, 25 °C, 18 h, 92 %; d) AD-mix-β (1.4 equiv), H2NSO2Me (1.0 equiv), NaHCO3 (3.0 equiv), tol., tBuOH, H2O, 0 °C, 36 h, 69 %, >95 % ee; e) 2-methoxypropene (5.0 equiv), PPTS (0.1 equiv), CH2Cl2, 25 °C, 18 h, 94 %; f) TMSOTf (1.35 equiv), Et3N (1.5 equiv), THF, 0 °C, 30 min; Pd(OAc)2 (0.1 equiv), O2 (balloon), DMSO, 25 °C, 18 h, 83 %; g) I2 (3.0 equiv), CH2Cl2, py, 25 °C, 30 min, 91 %. Bn = benzyl, MeCN = acetonitrile, OAc = acetate, SEM = 2-(trimethylsilyl) ethoxymethyl, DMF = dimethylformamide, tol = toluene, tBu = tert-butyl, PPTS = pyridinium, 4-toluenesulfonate, TMS = trimethylsilyl, Tf = trifluoromethanesulfonyl, DMSO = dimethyl sulfoxide, py = pyridine.