Skip to main content
. Author manuscript; available in PMC: 2020 Apr 19.
Published in final edited form as: Org Lett. 2019 Apr 8;21(8):2957–2961. doi: 10.1021/acs.orglett.9b01126

Scheme 5. Fragment Coupling and Final Stepsa.

Scheme 5.

aReaction conditions: (a) 27 (2 equiv), BF3·OEt2 (2 equiv), 4Å MS, CH2Cl2, 0 °C, 1 h, 78%; (b) Me3P (2.5 equiv), H2O (5 equiv)), THF, 0 °C to rt, 3 h, 70%; (c) 9 (2 equiv), Pd(PPh3)4 (1.2 equiv), TlOEt (1.5 equiv), THF/H2O (3/1), rt, 0 min, 74%; (d) Grubbs II (20 mol%), PhMe, reflux, 20 h, 65%; (e) py·HF, THF, rt, 36 h; (f) Et3N, MeOH, rt, 12 h, 42% (2 steps).