| abstract |
The invention pertains to a process for producing a compound of formula (11) wherein R 7 and R 8 are each independently selected from H, halogen, alkyl, aryl, or alkylaryl, R 42 is H or a protective group, R 43 is H or R 3 , wherein R 3 is a protective group, by contacting a compound of formula (10) with an olefmation reagent, wherein compound of formula (10) comprises a counter acid X 1 when R 42 ═H and R 43 ═H. |