PURPOSE: To obtain a vitamin D3 derivative by a coupling reaction using a palladium catalyst, useful as a medicine.
CONSTITUTION: The 1α,24-dihydroxy-22(E)-dehydrovitamin D3 of formula I [R is H, a tri(alkyl)silyl, etc.; R2 and R3 are each a triarylsilyl, etc.; X i s I or Br; A and B are each H or bonded to form a C-C bond] and its derivative such as (1S,1'E,3R,5Z,7E,20R)-9-10)-seco-20-(3'-cyclopropyl-3'-hydroxy-prop-1'- enyl)-1,3-dihydroxypregna--5,7,10(19)-triene. The compound, for example, is obtained by reacting a compound of formula II with a compound of formula III in the presence of a palladium catalyst. The catalyst used is preferably 0 valent or divalent organopalladium compound {e.g. tetrakis(triphenylphosphine) palladium} or a trisubstituted phosphorus compound {e.g. tributylphosphine}.
OSHIDA JUNICHI
TANAKA TOSHIO
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