Aromatic compounds 2a-c, analogs of la,25-dihydroxyitamin (calcitriol, l), and heteroaromatic compounds 4a-c and 5a-c, analogs of 19-nor-la,25-dihydroxyvitamin D3 (31, were designed to simulate the topology of their biologically potent parent compounds while avoiding previtamin D equilibrium. Convergent and facile total syntheses of the analogs (+)-2b, (+)-2c, (-)-4b, and (-)-5b were achieved via carbonyl addition of regiospecifically formed organolithium ...
