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CC BY-NC-ND 4.0 · SynOpen 2021; 05(01): 29-35
DOI: 10.1055/s-0040-1706016
paper

Development of a Continuous Photochemical Benzyne-Forming Process

Cormac Bracken 
a   School of Chemistry, University College Dublin, Science Centre South, D04 N2E2, Dublin, Ireland
,
Andrei S. Batsanov 
b   Department of Chemistry, University of Durham, South Road, DH1 3LE, Durham, UK
,
Marcus Baumann  ∗
a   School of Chemistry, University College Dublin, Science Centre South, D04 N2E2, Dublin, Ireland
› Author AffiliationsThis research has been enabled through funding by SSPC (European Regional Development Fund; 12/RC2275_P2) and instrumentation acquired through a recent Science Foundation Ireland Infrastructure Call 2018 (18/RI/5702). We gratefully acknowledge support from the School of Chemistry at UCD for a PhD scholarship (to CB). Support of our research through a RSC Research Enablement Grant (E20-2998 to MB) is acknowledged.
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Abstract

A continuous-flow process is presented that enables the safe generation and derivatization of benzyne under photochemical conditions. This is facilitated by a new high-power LED lamp emitting light at 365 nm. The resulting flow process effectively controls the release of gaseous by-products based on an adjustable backpressure regulator and delivers a series of heterocyclic products in a short residence time of 3 minutes. The robustness of this methodology is demonstrated for the rapid generation of benzotriazoles, 2H-indazoles and various furan-derived adducts, facilitating the preparation of these important heterocyclic scaffolds via a simple and readily scalable flow protocol.

Key words

flow chemistry - photochemistry - benzyne - cycloadditions - high-energy intermediates - reaction development - heterocycles

Supporting Information

    Supporting information for this article is available online at https://doi.org/10.1055/s-0040-1706016.
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Publication History

Received: 23 December 2020

Accepted after revision: 07 January 2021

Article published online:
01 February 2021

© 2021. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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