Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition

Bo Zhu; Richmond Lee; Jiangtao Li; Xinyi Ye; San-Ni Hong; Shuai Qiu; Michelle L. Coote; Zhiyong Jiang

doi:10.1002/anie.201507796

Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition

Bo Zhu, Richmond Lee, Jiangtao Li, Xinyi Ye, San-Ni Hong, Shuai Qiu, Michelle L. Coote, Zhiyong Jiang

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

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Abstract

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report a synthetic strategy for a chemoselective switch and a diastereo-divergent approach for the asymmetric reaction of 5H-oxazol-4-ones and N-itaconimides catalyzed by L-tert-leucine-derived tertiary amine-urea compounds. The reaction was modulated to harness either tandem conjugate addition-protonation or [4+2] cycloaddition as major product with excellent enantio- and diastereoselectivities. Subjecting the enantio-enriched cycloaddition products to a basic silica gel reagent yields the diastereomer vis-à-vis the product directly obtained under conditions for addition-protonation, thus opening a diastereo-divergent route for creating 1,3-tertiary-hetero-quaternary stereocenters. Quantum chemical studies further provide stereochemical analysis for the [4+2] process and a plausible mechanism for this chemoselective switch is proposed.

Original language	English (US)
Pages (from-to)	1299-1303
Number of pages	5
Journal	Angewandte Chemie International Edition
Volume	55
Issue number	4
DOIs	https://doi.org/10.1002/anie.201507796
State	Published - Dec 9 2015
Externally published	Yes

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@article{10980aafef664e1990a0c893b796cef2,

title = "Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition",

abstract = "{\textcopyright} 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report a synthetic strategy for a chemoselective switch and a diastereo-divergent approach for the asymmetric reaction of 5H-oxazol-4-ones and N-itaconimides catalyzed by L-tert-leucine-derived tertiary amine-urea compounds. The reaction was modulated to harness either tandem conjugate addition-protonation or [4+2] cycloaddition as major product with excellent enantio- and diastereoselectivities. Subjecting the enantio-enriched cycloaddition products to a basic silica gel reagent yields the diastereomer vis-{\`a}-vis the product directly obtained under conditions for addition-protonation, thus opening a diastereo-divergent route for creating 1,3-tertiary-hetero-quaternary stereocenters. Quantum chemical studies further provide stereochemical analysis for the [4+2] process and a plausible mechanism for this chemoselective switch is proposed.",

author = "Bo Zhu and Richmond Lee and Jiangtao Li and Xinyi Ye and San-Ni Hong and Shuai Qiu and Coote, {Michelle L.} and Zhiyong Jiang",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: Z.J. is grateful for the grants from NSFC (grant number21072044), NCET-11-0938 and the Program for InnovativeResearch Team from the University of Henan Province(14IRTSTHN006). M.L.C. gratefully acknowledges generousallocations of supercomputing time on the National Facility ofthe National Computational Infrastructure, and financialsupport from the Australian Research Council. R.L. alsoacknowledges Dr. Xiaohe Miao (KAUST) for supplementarycomputing time. This publication acknowledges KAUST support, but has no KAUST affiliated authors.",

year = "2015",

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doi = "10.1002/anie.201507796",

language = "English (US)",

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pages = "1299--1303",

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T1 - Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition

AU - Zhu, Bo

AU - Lee, Richmond

AU - Li, Jiangtao

AU - Ye, Xinyi

AU - Hong, San-Ni

AU - Qiu, Shuai

AU - Coote, Michelle L.

AU - Jiang, Zhiyong

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: Z.J. is grateful for the grants from NSFC (grant number21072044), NCET-11-0938 and the Program for InnovativeResearch Team from the University of Henan Province(14IRTSTHN006). M.L.C. gratefully acknowledges generousallocations of supercomputing time on the National Facility ofthe National Computational Infrastructure, and financialsupport from the Australian Research Council. R.L. alsoacknowledges Dr. Xiaohe Miao (KAUST) for supplementarycomputing time. This publication acknowledges KAUST support, but has no KAUST affiliated authors.

PY - 2015/12/9

Y1 - 2015/12/9

N2 - © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report a synthetic strategy for a chemoselective switch and a diastereo-divergent approach for the asymmetric reaction of 5H-oxazol-4-ones and N-itaconimides catalyzed by L-tert-leucine-derived tertiary amine-urea compounds. The reaction was modulated to harness either tandem conjugate addition-protonation or [4+2] cycloaddition as major product with excellent enantio- and diastereoselectivities. Subjecting the enantio-enriched cycloaddition products to a basic silica gel reagent yields the diastereomer vis-à-vis the product directly obtained under conditions for addition-protonation, thus opening a diastereo-divergent route for creating 1,3-tertiary-hetero-quaternary stereocenters. Quantum chemical studies further provide stereochemical analysis for the [4+2] process and a plausible mechanism for this chemoselective switch is proposed.

AB - © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report a synthetic strategy for a chemoselective switch and a diastereo-divergent approach for the asymmetric reaction of 5H-oxazol-4-ones and N-itaconimides catalyzed by L-tert-leucine-derived tertiary amine-urea compounds. The reaction was modulated to harness either tandem conjugate addition-protonation or [4+2] cycloaddition as major product with excellent enantio- and diastereoselectivities. Subjecting the enantio-enriched cycloaddition products to a basic silica gel reagent yields the diastereomer vis-à-vis the product directly obtained under conditions for addition-protonation, thus opening a diastereo-divergent route for creating 1,3-tertiary-hetero-quaternary stereocenters. Quantum chemical studies further provide stereochemical analysis for the [4+2] process and a plausible mechanism for this chemoselective switch is proposed.

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JO - Angewandte Chemie International Edition

JF - Angewandte Chemie International Edition

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ER -

Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition

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