在室温下,在化学计量或催化量的三乙胺存在下,丙二酸半硫酯(MAHT)和丙二酸半氧基酯(MAHO)与酮和醛亲电子发生脱羧亲核加成反应。在无金属条件下进行这些反应的能力使得能够对导致1的反应路径进行详细的机理分析。亲核后加成/脱羧前中间体的1 H NMR光谱表征和该中间体可逆形成后不可逆脱羧的实验证据。还确定了反应路径中每个键形成/键断裂步骤的速率常数,从而阐明了在这些过程中MAHO和MAHT亲核试剂之间不同的反应性。最后,通过这些研究获得的机理见解已被用于开发新的脱羧香豆素合成方法。
Decarboxylative Ketone Aldol Reactions: Development and Mechanistic Evaluation under Metal-Free Conditions
作者:Nicole Blaquiere、Daniel G. Shore、Sophie Rousseaux、Keith Fagnou
DOI:10.1021/jo901022j
日期:2009.8.21
acid half oxyesters (MAHOs) are shown to undergo decarboxylative nucleophilic addition reactions with ketone and aldehyde electrophiles in the presence of stoichiometric or catalytic quantities of triethylamine at room temperature. The ability to perform these reactions undermetal-freeconditions has enabled a detailed mechanistic analysis of the reaction pathway leading to the 1H NMR spectroscopic
在室温下,在化学计量或催化量的三乙胺存在下,丙二酸半硫酯(MAHT)和丙二酸半氧基酯(MAHO)与酮和醛亲电子发生脱羧亲核加成反应。在无金属条件下进行这些反应的能力使得能够对导致1的反应路径进行详细的机理分析。亲核后加成/脱羧前中间体的1 H NMR光谱表征和该中间体可逆形成后不可逆脱羧的实验证据。还确定了反应路径中每个键形成/键断裂步骤的速率常数,从而阐明了在这些过程中MAHO和MAHT亲核试剂之间不同的反应性。最后,通过这些研究获得的机理见解已被用于开发新的脱羧香豆素合成方法。
Kinetic Resolution of Quaternary and Tertiary β-Hydroxy Esters
作者:Derek J. Schipper、Sophie Rousseaux、Keith Fagnou
DOI:10.1002/anie.200902373
日期:2009.10.19
Selectivity factors: The resolution of tertiary and secondary alcohols, which arise from ketone and aldehyde aldol additions, proceeds in the presence of (1S,2R)‐N‐methylephedrine (see example). The method is technically simple, easily scalable, and provides tertiary and secondary alcohols in high enantiomeric ratios.