Synthesis of a 1α,25-dihydroxyvitamin D<sub>3</sub>A ring model by an acyl radical cyclization
作者:Duncan Batty、David Crich、Simon M. Fortt
DOI:10.1039/c39890001366
日期:——
The synthesis of (±)-(2), an A ringmodel for 1α,25-dihydroxyvitamin D3 has been achieved in 7 steps from ethyl acetoacetate, with an acylradicalcyclization as the key ring forming step.
The regioselective hydroboration of ethyl (3R, 5S)-3,5-isopropylidenedioxy-6-heptynoate, followed by the cross-coupling reaction with an aryl halide, provides ethyl (3R, 5S, 6E)-7-aryl-3,5-isopropylidenedioxy-6-heptenoate, a precursor of a highly potent HMG-CoA reductase inhibitor NK-104.