Pd-catalyzed synthesis of 2-alkynyl derivatives of 19β,28-epoxy-18α-olean-1-en-3-one
作者:R. N. Shakhmaev、A. Sh. Sunagatullina、E. A. Abdullina、V. V. Zorin
DOI:10.1134/s1070428017110173
日期:2017.11
Basing on Sonogashira reaction of 2-iodo-19 beta, 28-epoxy-18 alpha-olean-1-en-3-one with alkynes an effective approach was developed to the synthesis of 2-alkynyl derivatives of 19 beta, 28-epoxy-18 alpha-olean-1-en-3-one. Initial 2-iodo-19 beta, 28-epoxy-18 alpha-olean-1-en-3-one was obtained by isomerization of the accessible betulin into allobetulin in the presence of Amberlyst 15, oxidation of allobetulin to 19 beta, 28-epoxy-18 alpha-olean-1-en-3-one under the action of 2-iodoxybenzoic acid, and iodination of the obtained enone in the presence of DMAP.