(a) i. NaOH solution (10%), THF,
25 °C; ii. 2,2-dimethoxy-propane, PTSA, DCM, 25 °C, no purification;
iii. Cs2CO3, i-PrI, DMF, 25 °C, 56% over
3 steps; (b) i. NaOH solution (10%), THF, 25 °C; ii. 2,2-dimethoxypropane,
PTSA, DCM, 25 °C; iii. TMSCH2N2, MeOH,
25 °C, 72% over 3 steps; (c) i. AcOH/H2O (80:20),
50 °C; ii. Cs2CO3, i-PrI, DMF, 25 °C,
59% over 2 steps; (d) i. AcOH/H2O (80:20), 50 °C;
ii. TMSCH2N2, DCM, 25 °C, 66% over 2 steps;
(e) TMSOTf, NIS, DCM, −25 °C, 81% for 32 and
75% for 34; (h) H2, Pd/C, dioxane, 23% for 33 and 20% for 35.