| abstract |
A process for preparing a compound represented by formula IA, wherein R is selected from the group consisting of hydrogen, alkyl and substituted alkyl; and X1 is an oxygen protecting group; comprising reacting a compound of formula IV, wherein X 1 is as defined above, with an aldehyde of formula V, RCHO Where R is as defined, in the presence of a suitable base to give a compound of formula III, wherein R and X1 are defined as iranium, further comprising reacting a compound of formula III with the appropriate oxidizing agent as a binast compound of formula II, wherein R and X1 are as defined above, and ultimately comprising reacting compound II with the appropriate reaction agent to form a compound of formula IA . The patent contains another 25 patent claims. |