De Novo Asymmetric Synthesis of Milbemycin β<sub>3</sub> via an Iterative Asymmetric Hydration Approach
作者:Miaosheng Li、George A. O'Doherty
DOI:10.1021/ol061439k
日期:2006.8.1
achieved in 22 steps and 2.8% overall yield from an achiral dienoate. The spiroketal ring system was installed by three sequential asymmetric hydrations followed by sprioketalization. Both the absolute and relative stereochemistry of milbemycin beta3 was introduced by two Sharpless asymmetric dihydroxylations, two pi-allylpalladium-catalyzed reductions, and an iridium-catalyzed hydrogen migration/Claisen