Base-induced cyclisation of ortho-substituted 2-phenyloxazolines to give 3-aminobenzofurans and related heterocycles

R Alan Aitken; Andrew David Harper; Alexandra Martha Zoya Slawin

doi:10.1055/s-0036-1588503

Base-induced cyclisation of ortho-substituted 2-phenyloxazolines to give 3-aminobenzofurans and related heterocycles

R Alan Aitken, Andrew David Harper, Alexandra Martha Zoya Slawin

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

Abstract

Treatment of ortho-benzyloxyphenyloxazolines with butyllithium and potassium t-butoxide results in cyclisation with ring-opening of the oxazoline to give 2-aryl-3-aminobenzofurans. The reaction also occurs with the corresponding benzylthio- and benzylamino-compounds to give benzothiophenes and indoles, respectively. Use of an ortho-allyloxyphenyloxazoline gives the corresponding 2-vinylbenzofuran, while both α-methylbenzyloxy and benzylsulfonyl compounds form stable spirooxazolidine products. The X-ray structure of an aminobenzothiophene product has been determined.

Original language	English
Pages (from-to)	1738-1742
Number of pages	5
Journal	Synlett
Volume	28
Issue number	14
Early online date	18 Jul 2017
DOIs	https://doi.org/10.1055/s-0036-1588503
Publication status	Published - 18 Aug 2017

Keywords

Cyclisation
Oxazoline
Benzofuran
Benzothiophenes
Indole
Schlosser’s base
Spiro heterocycle

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10.1055/s-0036-1588503

17SL_Aitken+HarperRev
© 2017 Georg Thieme Verlag Stuttgart · New York. This work has been made available online in accordance with the publisher’s policies. This is the author created accepted version manuscript following peer review and as such may differ slightly from the final published version. The final published version of this work is available at: https://doi.org/10.1055/s-0036-1588503
Accepted author manuscript, 467 KB

Cite this

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title = "Base-induced cyclisation of ortho-substituted 2-phenyloxazolines to give 3-aminobenzofurans and related heterocycles",

abstract = "Treatment of ortho-benzyloxyphenyloxazolines with butyllithium and potassium t-butoxide results in cyclisation with ring-opening of the oxazoline to give 2-aryl-3-aminobenzofurans. The reaction also occurs with the corresponding benzylthio- and benzylamino-compounds to give benzothiophenes and indoles, respectively. Use of an ortho-allyloxyphenyloxazoline gives the corresponding 2-vinylbenzofuran, while both α-methylbenzyloxy and benzylsulfonyl compounds form stable spirooxazolidine products. The X-ray structure of an aminobenzothiophene product has been determined.",

keywords = "Cyclisation, Oxazoline, Benzofuran, Benzothiophenes, Indole, Schlosser{\textquoteright}s base, Spiro heterocycle",

author = "Aitken, {R Alan} and Harper, {Andrew David} and Slawin, {Alexandra Martha Zoya}",

note = "The authors thank EPSRC (UK) for a DTA studentship (Grant No. EP/L505079/1) and the EPSRC UK National Mass Spectrometry Facility at Swansea University",

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T1 - Base-induced cyclisation of ortho-substituted 2-phenyloxazolines to give 3-aminobenzofurans and related heterocycles

AU - Aitken, R Alan

AU - Harper, Andrew David

AU - Slawin, Alexandra Martha Zoya

N1 - The authors thank EPSRC (UK) for a DTA studentship (Grant No. EP/L505079/1) and the EPSRC UK National Mass Spectrometry Facility at Swansea University

PY - 2017/8/18

Y1 - 2017/8/18

N2 - Treatment of ortho-benzyloxyphenyloxazolines with butyllithium and potassium t-butoxide results in cyclisation with ring-opening of the oxazoline to give 2-aryl-3-aminobenzofurans. The reaction also occurs with the corresponding benzylthio- and benzylamino-compounds to give benzothiophenes and indoles, respectively. Use of an ortho-allyloxyphenyloxazoline gives the corresponding 2-vinylbenzofuran, while both α-methylbenzyloxy and benzylsulfonyl compounds form stable spirooxazolidine products. The X-ray structure of an aminobenzothiophene product has been determined.

AB - Treatment of ortho-benzyloxyphenyloxazolines with butyllithium and potassium t-butoxide results in cyclisation with ring-opening of the oxazoline to give 2-aryl-3-aminobenzofurans. The reaction also occurs with the corresponding benzylthio- and benzylamino-compounds to give benzothiophenes and indoles, respectively. Use of an ortho-allyloxyphenyloxazoline gives the corresponding 2-vinylbenzofuran, while both α-methylbenzyloxy and benzylsulfonyl compounds form stable spirooxazolidine products. The X-ray structure of an aminobenzothiophene product has been determined.

KW - Cyclisation

KW - Oxazoline

KW - Benzofuran

KW - Benzothiophenes

KW - Indole

KW - Schlosser’s base

KW - Spiro heterocycle

UR - https://www.thieme-connect.de/media/synlett/EFirst/supmat/sup_st-2017-b0311-l_10-1055_s-0036-1588503.pdf

U2 - 10.1055/s-0036-1588503

DO - 10.1055/s-0036-1588503

M3 - Article

SN - 0936-5214

VL - 28

SP - 1738

EP - 1742

JO - Synlett

JF - Synlett

IS - 14

ER -

Base-induced cyclisation of ortho-substituted 2-phenyloxazolines to give 3-aminobenzofurans and related heterocycles

Abstract

Keywords

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