a) Ba(OH)2.8H2O, THF, then 2 in THF: H2O (40:1) 0 °C; b) (R)-2-Me-CBS-oxazaborolidine (0.5 eq), BH3.Me2S (1.5 eq), CH2Cl2, 0 °C, then 4, 0 °C, 2 h, then ethanolamine; c) TBSOTf, 2,6-lutidine, CH2Cl2, −78 °C; d) HF (40% aq.), glass splinters, MeCN:Et2O (1:1), 0 °C; e) Dess-Martin periodinane, CH2Cl2.