Total synthesis of 25-Hydroxy-16,23E-diene Vitamin D3 and 1α,25-Dihydroxy-16,23E-diene Vitamin D3: separation of genomic and nongenomic vitamin D Activities

Separation of genomic and nongenomic vitamin D activities was achieved by structural modification of 1,25-dihydroxy vitamin D3 by introduction of 16 and 23E double bonds. The modified compound 3, lacking a 1 alpha-hydroxy group, exhibits only nongenomic activity. Its 1 alpha-hydroxy relative 4 expresses fully both genomic and non-genomic activities. A total synthesis of analogues 3 and 4 is described.