Scheme 2. Synthesis of 1-deoxy-l-fuconojirimycin 6. Reagents and conditions: (a) (i) Et2O, DIBAL-H, –80 °C, (ii) MeOH, –90 °C, (iii) amine 29, NaOMe, (iv) NaBH4, –15 °C to rt, 88%; (b) Boc2O, 50 °C, 100%; (c) Grubbs 1st generation, CH2Cl2, 88%; (d) (i) K2OSO4·2H2O, NMO, acetone–H2O (1 : 1), –10 °C, (ii) Ac2O, pyridine, DMAP, 0 °C, 88% (33 : 34 = 1 : 3); (e) (i) K2CO3, MeOH, (ii) TBAF, THF, (iii) 6M HCl, MeOH, 71%.
