Reagents
and conditions: (i)
Br2, NaOAc buffer, 89%; (ii) Na2Cl4Pd, PhB(OH)2, TPPTS, Na2CO3, MeCN–H2O, 80 °C, 1h, 81%; (iii) 75% aq TFA, rt; (iv) POCl3, TEP, 0 °C, 1 h; (v) morpholine, PPh3, dipyridyldisulfide,
DMSO, rt, 1 h then cyclopentylphosphate 79, MnCl2 in formamide, MgSO4, rt, 16 h, 12%.