Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
J Org Chem. 2012 Jan 6;77(1):543-55. doi: 10.1021/jo2021289. Epub 2011 Dec 1.
A method of preparing enantiopure hydroxy-γ-butyrolactones containing multiple contiguous stereocenters in high yield with good diastereoselectivity has been developed. Osmium tetroxide mediated dihydroxylation of a range of β-alkenyl-β-hydroxy-N-acyloxazolidin-2-ones results in formation of triols that undergo spontaneous intramolecular 5-exo-trig cyclization reactions to provide hydroxy-γ-butyrolactones. The stereochemistry of these hydroxy-γ-butyrolactones has been established using NOE spectroscopy, which revealed that 1-substituted, 1,1-disubstituted, (E)-1,2-disubstituted, (Z)-1,2-disubstituted, and 1,1,2-trisubstituted alkenes undergo dihydroxylation with anti-diastereoselectivity, while 1,2,2-trisubstituted systems afford syn-diastereoisomers. The synthetic utility of this methodology has been demonstrated for the asymmetric synthesis of the natural product 2-deoxy-D-ribonolactone.
已经开发出一种高产率、高对映选择性地制备含有多个连续手性中心的手性纯羟基-γ-丁内酯的方法。一系列β-烯基-β-羟基-N-酰基恶唑烷-2-酮的高碘酸钠介导的双羟化反应导致三醇的形成，三醇自发进行分子内 5-endo-trig 环化反应，提供羟基-γ-丁内酯。这些羟基-γ-丁内酯的立体化学结构已通过 NOE 光谱学确定，这表明 1-取代、1,1-二取代、(E)-1,2-二取代、(Z)-1,2-二取代和 1,1,2-三取代烯烃具有反式对映选择性的双羟化反应，而 1,2,2-三取代体系则得到顺式对映异构体。该方法学的合成实用性已通过天然产物 2-脱氧-D-核糖内酯的不对称合成得到证明。
