Preparation of a 24-Nor-1,4-dien-3-one Triterpene Derivative from Betulin: A New Route to 24-Nortriterpene Analogues<sup>1</sup>
作者:Yonghong Deng、John K. Snyder
DOI:10.1021/jo010929h
日期:2002.5.1
A newroute to 24-nortriterpene derivatives with 2-hydroxy-Delta(1,4)-cyclohexadien-3-one A-rings from triterpene precursors has been demonstrated beginning with betulin to prepare derivatives of betulinic acid. The key steps in the transformation are a Suárez cleavage of the A-ring with a subsequent SmI(2)-mediated pinacol-type coupling to reclose the A-ring following removal of the C-24 carbon by