1993-03-9Relevant articles and documents
Protodeboronation of (Hetero)Arylboronic Esters: Direct versus Prehydrolytic Pathways and Self-/Auto-Catalysis
Hayes, Hannah L. D.,Wei, Ran,Assante, Michele,Geogheghan, Katherine J.,Jin, Na,Tomasi, Simone,Noonan, Gary,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information, p. 14814 - 14826 (2021/09/13)
The kinetics and mechanism of the base-catalyzed hydrolysis (ArB(OR)2→ ArB(OH)2) and protodeboronation (ArB(OR)2→ ArH) of a series of boronic esters, encompassing eight different polyols and 10 polyfluoroaryl and heteroaryl moieties, have been investigated by in situ and stopped-flow NMR spectroscopy (19F,1H, and11B), pH-rate dependence, isotope entrainment,2H KIEs, and KS-DFT computations. The study reveals the phenomenological stability of boronic esters under basic aqueous-organic conditions to be highly nuanced. In contrast to common assumption, esterification does not necessarily impart greater stability compared to the corresponding boronic acid. Moreover, hydrolysis of the ester to the boronic acid can be a dominant component of the overall protodeboronation process, augmented by self-, auto-, and oxidative (phenolic) catalysis when the pH is close to the pKaof the boronic acid/ester.
Flow Chemistry on Multigram Scale: Continuous Synthesis of Boronic Acids within 1 s
Hafner, Andreas,Meisenbach, Mark,Sedelmeier, Joerg
supporting information, p. 3630 - 3633 (2016/08/16)
The benefits and limitations of a simple continuous flow setup for handling and performing of organolithium chemistry on the multigram scale is described. The developed metalation platform embodies a valuable complement to existing methodologies, as it combines the benefits of Flash Chemistry (chemical synthesis on a time scale of 1 s) with remarkable throughput (g/min) while mitigating the risk of blockages.
Preparation method of benzochromene derivative
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Paragraph 0093; 0094; 0095, (2016/10/31)
The invention discloses a preparation method of a benzochromene derivative shown as a formula (I). The benzochromene derivative can be taken as a synthesis intermediate of a drug such as a synthesis intermediate of Velpatasvir. Cheap and available 2-fluoro halogenated benzene is taken as a starting material, a brand-new synthetic route for preparing the benzochromene derivative is provided, the total yield of the whole reaction route is high, and the method is suitable for large-scale industrial production.