| abstract |
Compound having structure (I) wherein n is an integer from 1 to 5; R 1 and R 2 are each independently and optionally substituted with C 1 -C 6 alkyl; W and X are each independently hydrogen or C 1 -C 6 alkyl; Y is O, S or NR 3 , wherein R 3 is hydrogen, C 1 -C 6 alkyl or a protecting group; Z is a CD ring structure, a steroid structure, or vitamin D, each of which optionally has one or more protected or unprotected substituents and / or one or more protecting groups.n n n This method, in the presence of a base, yields a compound having structure (IV), wherein W, X, Y and Z are as defined above, in which structure (V) or (V ′) where n, R 1 and R 2 Is as defined above and E is a eliminator. |