Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones

Hon Eong Ho; Angela Pagano; James A. Rossi-Ashton; James R. Donald; Ryan G. Epton; Jonathan C. Churchill; Michael J. James; Peter O'Brien; Richard J.K. Taylor; William P. Unsworth

doi:10.1039/c9sc05311e

Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones

Hon Eong Ho, Angela Pagano, James A. Rossi-Ashton, James R. Donald, Ryan G. Epton, Jonathan C. Churchill, Michael J. James, Peter O'Brien, Richard J.K. Taylor^*, William P. Unsworth

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

Indole-tethered ynones form an intramolecular electron donor-acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols. This initiates a novel radical chain sequence, based on dearomatising spirocyclisation with concomitant C-S bond formation. Sulfur-containing spirocycles are formed in high yields using this simple and mild synthetic protocol, in which neither transition metal catalysts nor photocatalysts are required. The proposed mechanism is supported by various mechanistic studies, and the unusual radical initiation mode represents only the second report of the use of an intramolecular electron donor-acceptor complex in synthesis.

Original language	English
Pages (from-to)	1353-1360
Number of pages	8
Journal	Chemical Science
Volume	11
Issue number	5
Early online date	13 Dec 2019
DOIs	https://doi.org/10.1039/c9sc05311e
Publication status	Published - 7 Feb 2020

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10.1039/c9sc05311e

c9sc05311e
© The Royal Society of Chemistry 2020
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title = "Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones",

abstract = "Indole-tethered ynones form an intramolecular electron donor-acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols. This initiates a novel radical chain sequence, based on dearomatising spirocyclisation with concomitant C-S bond formation. Sulfur-containing spirocycles are formed in high yields using this simple and mild synthetic protocol, in which neither transition metal catalysts nor photocatalysts are required. The proposed mechanism is supported by various mechanistic studies, and the unusual radical initiation mode represents only the second report of the use of an intramolecular electron donor-acceptor complex in synthesis.",

author = "Ho, {Hon Eong} and Angela Pagano and Rossi-Ashton, {James A.} and Donald, {James R.} and Epton, {Ryan G.} and Churchill, {Jonathan C.} and James, {Michael J.} and Peter O'Brien and Taylor, {Richard J.K.} and Unsworth, {William P.}",

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AU - Ho, Hon Eong

AU - Pagano, Angela

AU - Rossi-Ashton, James A.

AU - Donald, James R.

AU - Epton, Ryan G.

AU - Churchill, Jonathan C.

AU - James, Michael J.

AU - O'Brien, Peter

AU - Taylor, Richard J.K.

AU - Unsworth, William P.

PY - 2020/2/7

Y1 - 2020/2/7

N2 - Indole-tethered ynones form an intramolecular electron donor-acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols. This initiates a novel radical chain sequence, based on dearomatising spirocyclisation with concomitant C-S bond formation. Sulfur-containing spirocycles are formed in high yields using this simple and mild synthetic protocol, in which neither transition metal catalysts nor photocatalysts are required. The proposed mechanism is supported by various mechanistic studies, and the unusual radical initiation mode represents only the second report of the use of an intramolecular electron donor-acceptor complex in synthesis.

AB - Indole-tethered ynones form an intramolecular electron donor-acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols. This initiates a novel radical chain sequence, based on dearomatising spirocyclisation with concomitant C-S bond formation. Sulfur-containing spirocycles are formed in high yields using this simple and mild synthetic protocol, in which neither transition metal catalysts nor photocatalysts are required. The proposed mechanism is supported by various mechanistic studies, and the unusual radical initiation mode represents only the second report of the use of an intramolecular electron donor-acceptor complex in synthesis.

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JO - Chemical Science

JF - Chemical Science

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Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones

Abstract

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Richard John Kenneth Taylor

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Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones

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Richard John Kenneth Taylor

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