Intramolecular Oxonium Ylide Formation–[2,3] Sigmatropic Rearrangement of Diazocarbonyl-Substituted Cyclic Unsaturated Acetals: A Formal Synthesis of Hyperolactone C
作者:David M. Hodgson、Stanislav Man、Kimberley J. Powell、Ziga Perko、Minxiang Zeng、Elena Moreno-Clavijo、Amber L. Thompson、Michael D. Moore
DOI:10.1021/jo501893r
日期:2014.10.17
4]non-2-ene-4,6-diones. The process creates adjacent quaternary stereocenters with full control of the relative stereochemistry. An unsymmetrical monomethylated cyclic unsaturated acetal leads to hyperolactone C, where ylide formation–rearrangement proceeds with high selectivity between subtly nonequivalent acetal oxygen atoms.
Rh(II)催化的氧鎓叶立德形成– [2,3]带有γ-环不饱和乙缩醛取代的α-重氮-β-酮酸酯的σ重排,然后进行酸催化的消除-内酯化,提供了一种简洁的方法来处理1,7 -二氧杂螺[4.4]非-2-烯-4,6-二酮。该过程在完全控制相对立体化学的情况下创建了相邻的四元立体中心。不对称的单甲基化环状不饱和缩醛会导致高内酯C,在此位置上,内酰胺不等价的缩醛氧原子之间会以较高的选择性进行内酯形成-重排。