[2,3] Wittig Rearrangement of β’-Hydroxyethyl Bis-Allylic Ethers: Highly Regiospecific Entry to Singly Dehydroxylated 19-Nor-1(or 3),25-dihydroxy-vitamin D3
摘要:
A conceptually new approach to regiospecific deprotonation at the alpha-position of beta'-hydroxyethyl bis-allylic ethers is shown on the basis of the dianion repulsion with the beta'-alkoxy anion, of which the [2,3] Wittig rearrangement product can be transformed to the A-rings of singly dehydroxylated 1(or 3),25-dihydroxy-19-nor-vitamin D-3 analogues to stimulate apoptosis or differentiation of HL-60 cancer cell.