Article

Stereoselective convergent synthesis of 24-substituted metabolites and analogues of vitamin D.

Departamento de Química Fundamental, Universidade da Coruña, E-15071 A Coruña, Spain.
The Journal of Steroid Biochemistry and Molecular Biology (impact factor: 3.05). 06/2004; 89-90(1-5):19-23. DOI:10.1016/j.jsbmb.2004.03.045 pp.19-23
Source: PubMed

ABSTRACT The synthesis of vitamin D(3) active metabolites [24R,25-(OH)(2)-D(3), 24S,25-(OH)(2)-D(3) and 1alpha,24R,25-(OH)(3)-D(3)] and the first 24-aminovitamin D(3) derivatives [24S-benzoylamino-25-OH-D(3) and 24S-benzoylamino-1alpha,25-(OH)(2)-D(3)] are reported. The stereogenic center at C-24 was generated through ultrasonically induced aqueous conjugate addition of iodide 8 to dioxolanone 6 or oxazolidinone 7. The vitamin D triene system was constructed using the Lythgoe approach. The synthetic route, which is both short (6 or 7 steps from iodide 8) and efficient (32-45% overall yield), constitutes a practical method for the preparation of 24-functionalized metabolites and analogues of vitamin D(3). The ultrasonically induced conjugate addition in the key step provides a novel example of a highly stereoselective reaction promoted by the zinc-copper couple in aqueous media.

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Keywords

7 steps
 
dioxolanone 6
 
efficient
 
key step
 
stereogenic center
 
stereoselective reaction
 
synthetic route
 
ultrasonically induced aqueous conjugate addition
 
ultrasonically induced conjugate addition
 
vitamin D triene system
 
zinc-copper couple