The thermal decarboxylation of peroxycholanic acid (1) leads by a radical chain reaction, to the epimeric 16-hydroxy, norcholanes (2) in > 35% yield; this regio-selective D-ring functionalization is the result of an intra-molecular homolytic 1,5-hydrogen shift.
过氧
胆酸(1)的热脱羧通过自由基链反应导致差向异构体16-羟基降
冰片烷(2)的收率> 35%;这种区域选择性的D-环官能化是分子内均溶的1,5-氢转移的结果。