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DOI: 10.1055/s-0040-1706479
Trapping of Transient Thienyllithiums Generated by Deprotonation of 2,3- or 2,5-Dibromothiophene in a Flow Microreactor
This work was financially supported by JSPS KAKENHI Grant Numbers JP16K05774 in Scientific Research (C), JP19H02717 in Scientific Research (B), JP16H01153 and JP18H04413 in the Middle Molecular Strategy.
In memory of Jun-ichi Yoshida
Abstract
Selective trapping of (4,5-dibromo-2-thienyl)lithium, known to undergo halogen dance, was achieved in a flow microreactor. This transient thienyllithium, generated by mixing 2,3-dibromothiophene and lithium diisopropylamide at –78 °C for 1.6 seconds, reacted with benzaldehyde. The reaction system is also applicable to other carbonyl compounds to afford the corresponding adducts in good yields. Moreover, the established conditions permit the conversion of 2,5-dibromothiophene into a mixture of the two constitutional isomers. The contrasting results are discussed on the basis of the reaction pathway.
Key words
halogen dance - microreactors - dibromothiophenes - substituent effects - deprotonation - lithiationSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0040-1706479.
- Supporting Information
Publication History
Received: 30 July 2020
Accepted after revision: 28 August 2020
Article published online:
15 October 2020
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