Construction of α-Halogenated Boronic Esters via Visible Light-Induced C–H Bromination
作者:Feng-Chen Gao、Ming Li、Heng-Yu Gu、Xin-Yi Chen、Shuang Xu、Yi Wei、Kai Hong
DOI:10.1021/acs.joc.3c01915
日期:2023.10.6
α-Halogenated boronic esters are versatile building blocks that can be diversified into a wide variety of polyfunctionalized molecules. However, their synthetic potential has been hampered by limited preparation methods. Herein, we report a visible light-induced C–H brominationreaction of readily available benzyl boronic esters. This method features high yields, mild conditions, simple operation,
Controllable Regiodivergent Alkynylation of 1,3‐Bis(Boronic) Esters Activated by Distinct Organometallic Reagents
作者:Ang Chen、Yang Qiao、De‐Wei Gao
DOI:10.1002/anie.202312605
日期:2023.11.27
An efficient method for controllable regiodivergent alkynylation of 1,3-bis(boronic) esters using distinct organometallicreagents has been developed. Mechanistic studies revealed that unique chelation patterns are essential in determining selectivity. This approach overcomes the drawbacks associated with coupling reactions through radical mechanisms, which commonly yield the classical products reacting
A simple and robust procedure for the synthesis and use of thermally unstable dichloromethyllithium in continuous flow mode is described. By utilizing residence times in the range of milliseconds for the generation and electrophilic quench of dichloromethyllithium, the straightforward synthesis of dichlorocarbinols and benzylic pinacol esters was realized at reaction temperatures of -30 degrees C, whereas typical temperatures in traditional batch mode are below, -78 degrees C. The excellent purity profile obtained from the flow process allows us to directly telescope the exiting flow stream into semibatch quenches for further modifications. All transformations gave the desired products in remarkable purity and yield on gram scale with no need for chromatography.
Matteson, Donald S.; Majumdar, Debesh, Organometallics, 1983, vol. 2, # 11, p. 1529 - 1535