Fast Carbon Isotope Exchange of Carboxylic Acids Enabled by Organic Photoredox Catalysis
作者:Duanyang Kong、Maxime Munch、Qiqige Qiqige、Christopher J. C. Cooze、Benjamin H. Rotstein、Rylan J. Lundgren
DOI:10.1021/jacs.0c12819
日期:2021.2.10
Carbazole/cyanobenzene photocatalysts promote the direct isotopic carboxylate exchange of C(sp3) acids with labeled CO2. Substrates that are not compatible with transition-metal-catalyzed degradation–reconstruction approaches or prone to thermally induced reversible decarboxylation undergo isotopic incorporation at roomtemperature in short reaction times. The radiolabeling of drug molecules and precursors
咔唑/氰基苯光催化剂促进带有标记CO 2的C(sp 3)酸的直接同位素羧酸交换。与过渡金属催化的降解-重建方法不兼容或易于发生热诱导的可逆脱羧作用的底物在室温下会在短时间内经历同位素掺入。证明了用[ 11 C] CO 2对药物分子和前体进行放射性标记。
How does an allene distort to accommodate negative charge? 1,1,3,3-Tetraphenylallene
作者:Andrzej Rajca、Laren M. Tolbert
DOI:10.1021/ja00240a030
日期:1987.3
Direct reversible decarboxylation from stable organic acids in dimethylformamide solution
作者:Duanyang Kong、Patrick J. Moon、Erica K. J. Lui、Odey Bsharat、Rylan J. Lundgren
DOI:10.1126/science.abb4129
日期:2020.7.31
chemically stable C(sp3) carboxylates, such as arylacetic acids and malonate half-esters, undergo uncatalyzed reversible decarboxylation in dimethylformamide solution. Decarboxylation-carboxylation occurs with substrates resistant to protodecarboxylation by Brønsted acids under otherwise identical conditions. Isotopically labeled carboxylic acids can be prepared in high chemical and isotopic yield by
CO2 的简单交换 羧酸中的二氧化碳 (CO2) 损失是生化和合成环境中的常见反应,但它通常涉及催化或长时间加热。孔等人。现在报告某些极性溶剂,如二甲基甲酰胺,它们本身会促进可逆的 CO2 损失,这些都是由一个碳桥接到芳环的羧酸盐。由于环上有吸电子取代基,即使在室温下,同位素标记的 CO2 也可以有效交换。或者,与醛的反应导致醇的形成。科学,这个问题 p。557 某些极性溶剂在令人惊讶的温和条件下使结合在苄基位点的 CO2 变得不稳定。有机化学中的许多经典和新兴方法依赖于二氧化碳 (CO2) 挤出来生成用于成键事件的反应中间体。涉及微观逆向的合成反应 - 反应中间体的羧化 - 通常使用非常不同的条件进行。我们报告化学稳定的 C(sp3) 羧酸盐,如芳基乙酸和丙二酸半酯,在二甲基甲酰胺溶液中经历未催化的可逆脱羧。脱羧 - 羧化发生在底物上,在其他条件相同的情况下,对布朗斯台德酸的原脱羧作用有
First Direct Structural Comparison of Complexes of the Same Metal Fragment to Ketenes in Both C,C- and C,O-Bonding Modes
作者:Douglas B. Grotjahn、Laura S. B. Collins、Marcus Wolpert、Galina A. Bikzhanova、H. Christine Lo、David Combs、John L. Hubbard
DOI:10.1021/ja004324z
日期:2001.8.1
Ph(2)C=(13)C=O and Ph(2)C=C=(18)O and their Ir(I) and Rh(I) complexes are reported, along with the generation of an Ir(I) complex of PhCH=(13)C=O. The effects of isotopic substitution on infraredabsorption data for ketene complexes are presented for the first time. Preliminary normal coordinate mode analysis allowed definitive assignment of absorptions ascribed to the C-O stretching frequencies of