Skip to main content
. Author manuscript; available in PMC: 2018 Jul 6.
Published in final edited form as: J Org Chem. 2018 Mar 5;83(13):7109–7120. doi: 10.1021/acs.joc.8b00094

Scheme 3. Synthesis of (ω − 2)-Hydroxyacyl Ascarosides threo-asc-7OH-ΔC9 (10a) and erythro-asc-7OH-ΔC9 (10b).

Scheme 3

Reagents and conditions: (i) 4-methoxybenzyl trichloroacetimidate, trimethylsilyl triflate, CH2Cl2, 0 °C, 3 h, 62%; (ii) DIBAL-H, CH2Cl2, −78 °C, 0.5 h, 100%; (iii): 4-pentenylmagnesium bromide, Et2O, 0 °C, 1 h, 58%; (iv) benzoyl chloride, pyridine, CH2Cl2, 0 °C, 12 h, 87% (18a); (v) benzoic acid, PPh3, DIAD, THF, 4 h, 55% (18b); (vi): ethyl acrylate, Grubbs second generation catalyst, CH2Cl2, 40 °C, 9 h, 76% (19a) and 81% (19b); (vii): DDQ, CH2Cl2/H2O, 1 h, 70% (20a) and 72% (20b); (viii): 2,4-di-O-benzoyl-ascarosyl-1-(2,2,2-trichloroacetimidate) (21), trimethylsilyl triflate, CH2Cl2, 0 °C, 3 h, 68% (22a) and 64% (22b); (ix): lithium hydroxide, water, MeOH, 12 h, 36% (10a), 46% (10b), 39% (23a), and 42% (23b)