Scheme 1.

Reagents and conditions (the scales refer to the single largest batches; where a second entry is given, it refers to the batch with the highest yield): a) pig liver esterase, aq. phosphate buffer, pH 7.1, 94 % (75 g scale); b) LiBHEt₃, THF, 0 °C→RT, then HCl, 98 % (ee=96 %, 28 g scale); c) KMnO₄, aq. acetone, 0 °C→RT, 71 % (27 g scale) or 97 % (280 mg scale); d) i) Ac₂O, 130 °C; ii) K₂CO₃, THF, 60 °C, 73 % (1 g scale) or 56 % (10 g scale); e) H₂ (1 atm), Pt/C (1.4 mol % Pt), EtOAc, NaOAc, 99 % (4 g scale); f) TBSOTf, 2,6-lutidine, CH₂Cl₂, 0 °C, 98 % (7 g scale); g) CCl₄, PPh₃, THF, reflux; h) MeLi, Fe(acac)₃ (10 mol %), 1,2-phenylenediamine (25 mol %), Et₂O, 0 °C, 55 % (over both steps, 3 g scale); i) ultrasonication of crude 10, CH₂Cl₂, 64 % (4.6 g scale); acac=acetylacetonate; TBS=tert-butyldimethylsilyl; Tf=trifluoromethanesulfonyl.