active ester bond through the classic organic name reaction, Baeyer–Villiger (BV) oxidation, and thus acetal esters and aryl esters were produced in high yields (up to 99%) at room temperature. Next, K2CO3 catalyzed the alcoholysis of the resulting ester products at 45 °C, affording various useful chemical platforms in excellent yields (up to 99%), such as phenols and multifunctional esters. This method
开发了一种用于木质素模型化合物的C–C键裂解的高效方法。惰性Ç α -C β或C α -C苯基的氧化木质素模型化合物通过键的经典有机名称反应成功地转化为活性酯键,拜尔-维利格(BV)的氧化,因此缩醛酯和芳基酯是在室温下以高收率(高达99%)生产。接下来,K 2 CO 3催化所得酯产物在45°C下的醇解反应,从而以优异的收率(高达99%)提供了各种有用的化学平台,例如苯酚和多功能酯。该方法使用可商购的试剂,不含过渡金属且简单,但高效,并且涉及温和的反应条件。
General and Selective Palladium-Catalyzed Oxidative Esterification of Alcohols
Selectively esterified: Primary alcohols react with dioxygen as a benign oxidant in a palladium‐catalyzed oxidativeesterification (see scheme). The corresponding aldehydes and esters are formed highly selectively depending on the catalyst system. The reactions take place in the presence of commercially available ligands without the need for additional organic hydrogen acceptors.
Efficient and selective palladium-catalyzed direct oxidative esterification of benzylic alcohols under aerobic conditions
作者:Yongke Hu、Bindong Li
DOI:10.1016/j.tet.2017.11.025
日期:2017.12
A highly efficient palladium-catalyzed approach for the direct oxidativeesterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions
Oxygen‐Controlled Catalysis by Vitamin B
<sub>12</sub>
‐TiO
<sub>2</sub>
: Formation of Esters and Amides from Trichlorinated Organic Compounds by Photoirradiation
作者:Hisashi Shimakoshi、Yoshio Hisaeda
DOI:10.1002/anie.201507782
日期:2015.12.14
An oxygen switch in catalysis of the cobalamin derivative (B12)‐TiO2 hybrid catalyst for the dechlorination of trichlorinated organiccompounds has been developed. The covalently bound B12 on the TiO2 surface transformed trichlorinated organiccompounds into an ester and amide by UV light irradiation under mild conditions (in air at room temperature), while dichlorostilbenes (E and Z forms) were formed
Efficient, scalable and economical preparation of tris(deuterium)- and<sup>13</sup>C-labelled<i>N</i>-methyl-<i>N</i>-nitroso-<i>p</i>-toluenesulfonamide (Diazald®) and their conversion to labelled diazomethane
作者:Samuel W. J. Shields、Jeffrey M. Manthorpe
DOI:10.1002/jlcr.3231
日期:2014.10
A method for the preparation of multi-gramme quantities of N-methyl-d3-N-nitroso-p-toluenesulfonamide (Diazald-d3) and N-methyl-13C-N-nitroso-p-toluenesulfonamide (Diazald-13C) and their conversion to diazomethane-d2 and diazomethane-13C, respectively, is presented. This approach uses robust and reliable chemistry, and critically, employs readily commercially available and inexpensive methanol as the label source. Several reactions of labelled diazomethane are also reported, including alkene cyclopropanation, phenol methylation and α-diazoketone formation, as well as deuterium scrambling in the preparation of diazomethane-d2 and subsequent methyl esterification of benzoic acid.