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. Author manuscript; available in PMC: 2019 May 3.
Published in final edited form as: J Am Chem Soc. 2018 Feb 5;140(6):2062–2066. doi: 10.1021/jacs.7b13189

Scheme 3. Total Synthesis of Xylogranatopyridine B (2).

Scheme 3.

aReagents and conditions: (a) LiCl (0.1 equiv), CuI (5 mol %), TMSCl (1.1 equiv), MeMgBr (1.2 equiv), −40 °C, THF, 10 min; (b) AgNO2 (1.2 equiv), TIPSCl (1.4 equiv), −40 °C, MeCN, 2 h; 10 (1.0 equiv), −40 to −20 °C, 2 h, 63% over 2 steps; (c) Ph3P=CH2 (3.0 equiv), PhMe, 23 to 60 °C, 1.5 h, 77%; (d) Bz2O (1.1 equiv), Et3N (2.0 equiv), DMAP (0.1 equiv), CH2Cl2 0 to 23 °C, 1 h, 80%; (1) O3, MeOH, −40 °C, 4 h; Cu(BF4)2 (1.5 equiv), Fe(BF4)2 (1.2 equiv), −40 to 23 °C, 1 h, 55%; (2) Bu3SnLi (1.2 equiv), [Pd(allyl)Cl]2 (2.5 mol %), diethyl allyl phosphate (1.0 equiv), THF, 60 °C, 1 min, 50%; (3) LDA (1.1 equiv), 14 (1.2 equiv), −78 °C, THF, 0.5 h, 88%; (4) Ac2O (2.0 equiv), py (3.0 equiv), DMAP (0.1 equiv), 0 °C, CH2Cl2, 0.5 h, 94%; (5) LiTMP (2.5 equiv), −78 to 23 °C, THF; Burgess reagent (3.0 equiv), 60 °C, 2 h, 67%; (6) Cu(OAc)2 (1.0 equiv), quinuclidine (2.0 equiv), 4 (1.5 equiv), 60 °C, DMF, 12 h; O2, 100 °C, 1 h, 43%; (7) Na[OCr(O2COC(CH3)C2H5)2] (10.0 equiv), 15-C-5 (0.5 equiv), 75 °C, MeCN, 14 h, 56% + 27% 3; (8) Zn(TMP)2 (1.4 equiv), [Pd(allyl)Cl]2 (5 mol %), diethyl allyl phosphate (1.2 equiv), 85 °C, 1 h, 67%; (9) TBSOTf (5 mol %), 1-(TBS)-1-methoxyethene (1.5 equiv), CH2Cl2, 0 to 23 °C, 0.5 h, 75%, 1:1 dr at C5; (10) Et2Zn (2.0 equiv), CH2I2 (4.0 equiv), 0 to 23 °C, PhMe, 6 h; TBAT (10.0 equiv) in THF, 12 h, 75%; (11) [PtCl2(C2H4)]2 (10 mol %), CH2Cl2, 23 °C, 5 h, 69%.