Kinetic and computational evidence for an intermediate in the hydrolysis of sulfonate esters
作者:Ann C. Babtie、Marcelo F. Lima、Anthony J. Kirby、Florian Hollfelder
DOI:10.1039/c2ob25699a
日期:——
occur by concerted mechanisms. We now report the observation of a break in a Brønsted correlation for the alkaline hydrolysis of aryl benzenesulfonates. On either side of a break-point, βleaving group values of −0.27 (pKa < 8.5) and −0.97 (pKa > 8.5) are measured. These data are consistent with a two-step mechanism involving a pentavalent intermediate that is also supported by QM/MM calculations. The
以前已经认为,磺酸酯的水解反应是通过协同机制发生的。现在,我们报告对芳基苯磺酸盐进行碱水解的布朗斯台德相关性破裂的观察结果。在断点的任一侧,测得的β离开基团值为-0.27(p K a <8.5)和-0.97(p K a > 8.5)。这些数据与涉及五价中间体的两步机制相一致,QM / MM计算也支持该机制。新兴的情况可以通过强亲核试剂与离去基团较弱的组合效应来解释,该组合基团迫使通常协调一致的反应有利于逐步进行。
Metal-Free Oxidative Formation of Aryl Esters by Catalytic Coupling of Acyl and Sulfonyl Chlorides with Arylboronic Acids
作者:Fang Liu、Akbar Sohail、Keyume Ablajan
DOI:10.1021/acs.joc.3c01151
日期:2024.1.5
synthesis of arylesters was developed through metal-free oxidation. This reaction employs stable and readily available acyl or sulfonyl chlorides and arylboronicacids as the starting materials and proceeds under mild reaction conditions without additional precious metal catalysts. This new strategy exhibits broad substrate tolerance and operational simplicity and gives diverse arylesters in moderate
Aryl Nitriles from Alkynes Using <i>tert</i>-Butyl Nitrite: Metal-Free Approach to C≡C Bond Cleavage
作者:Uttam Dutta、David W. Lupton、Debabrata Maiti
DOI:10.1021/acs.orglett.6b00147
日期:2016.2.19
AlkyneC≡Cbond breaking, outside of alkyne metathesis, remains an underdeveloped area in reaction discovery. Recently, nitrogenation has been reported to allow nitrile formation from alkynes. A new protocol for the metal-free C≡Cbondcleavage of terminal alkynes to produce nitriles is reported. This method provides an opportunity to synthesize a vast range of nitriles containing aryl, heteroaryl