Observation of a Transient Intermediate in Soai’s Asymmetric Autocatalysis: Insights from 1H NMR Turnover in Real Time
作者:Timo Gehring、Michela Quaranta、Barbara Odell、Donna G. Blackmond、John M. Brown
DOI:10.1002/anie.201203398
日期:2012.9.17
Caught in the act: 1HNMR spectroscopy was used to monitor the loss of reactant and formation of product during the induction and burst phases of Soai'sautocatalysis reaction. A transientintermediate was observed at 0 °C and identified as an alkoxyacetal formed from one aldehyde and two alkoxide moieties (see picture).
参与其中:1 H NMR光谱用于监测Soai自催化反应的诱导阶段和猝发阶段期间反应物的损失和产物的形成。在0°C时观察到一个过渡中间体,并鉴定为由一个醛和两个醇盐部分形成的烷氧基缩醛(参见图片)。
Unusual Inverse Temperature Dependence on Reaction Rate in the Asymmetric Autocatalytic Alkylation of Pyrimidyl Aldehydes
作者:Michela Quaranta、Timo Gehring、Barbara Odell、John M. Brown、Donna G. Blackmond
DOI:10.1021/ja103204w
日期:2010.11.3
Observations of an intriguing inverse temperature dependence on reactionrate and a profound induction period in the Soai autocatalytic reaction are reported along with detailed kinetic and NMR investigations of the product alkoxide at low temperatures, leading to the suggestion that the active catalyst is derived in situ from the tetrameric ground state.
the highest enhancements of enantiomeric excess reported so far in the Soai reaction in one reaction cycle (7.2→94.1 % ee or 3.1→92.1 % ee). Our results led to a set of reaction parameters that yield reproducible results. Therefore, our new startingmaterial 1 g is suitable for systematic and mechanistic studies on this remarkable reaction. A series of experiments designed to quantify the amplification