作者:Andreas Habel、Wilhelm Boland
DOI:10.1039/b801514g
日期:——
An efficient and highly flexible synthesis for chiral γ- and δ-lactones with high enantiomeric purity is described (>99% ee and 57â87% overall yield). The protocol involves alkylation of chiral 1,2-oxiranes with terminally unsaturated Grignard reagents. Subsequent oxidative degradation (OsO4âOxone) of the terminal double bond from chiral alk-1-en-5-ols and alk-1-en-6-ols affords 4- or 5-hydroxy acids and γ- and δ-lactones after acidic workup. The flexibility and efficiency of the protocol is illustrated by the synthesis of several alkanolides and alkenolides, hydroxy fatty acids and dihydroisocoumarins.
描述了一种高效且高度灵活的合成方法,用于制备具有高对映体纯度的手性γ-和δ-内酯(>99% ee和57–87%总体产率)。该方法涉及用末端不饱和的格氏试剂对手性1,2-氧杂环丁烷进行烷基化。随后,手性alk-1-en-5-醇和alk-1-en-6-醇的末端双键经过氧化降解(OsO4–Oxone),在酸性处理后可得到4-或5-羟基酸以及γ-和δ-内酯。通过合成几种烷醇内酯和烯醇内酯、羟基脂肪酸和二氢异香豆素,展示了该方法的灵活性和高效性。