Switchable Chemoselectivity for Organocatalytic, Asymmetric Malononitrile Addition to ortho-Formyl Chalcones

Sanjay Maity; Mithu Saha; Gurupada Hazra; Prasanta Ghorai

doi:10.1021/acs.orglett.7b02862

Switchable Chemoselectivity for Organocatalytic, Asymmetric Malononitrile Addition to ortho-Formyl Chalcones

Sanjay Maity, Mithu Saha, Gurupada Hazra, Prasanta Ghorai

Chemistry (Twin Cities)

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

19 Scopus citations

Abstract

Chemoselective 1,2- and 1,4-addition of malononitriles to ortho-formyl chalcones using cinchona alkaloid based bifunctional chiral organocatalysts has been shown by tuning the electronic nature of the malononitriles. Alkyl (hard) malononitriles undergo an asymmetric 1,2-addition followed by oxa-Michael reaction cascade to afford 1,3-disubstituted isobenzofurans with high enantio- and diastereoselectivity. Aryl (soft) malononitriles proceed through 1,4-addition followed by an aldol reaction cascade to provide indanols, having three consecutive stereocenters, in good yields and with good to excellent enantio- and diastereoselectivites.

Original language	English (US)
Pages (from-to)	5872-5875
Number of pages	4
Journal	Organic Letters
Volume	19
Issue number	21
DOIs	https://doi.org/10.1021/acs.orglett.7b02862
State	Published - Nov 3 2017

Bibliographical note

Funding Information:
This work is funded by SERB (EMR/2016/005995), New Delhi, and IISER Bhopal. S.M. thanks UGC. M.S. thanks IISERB. G.H. thanks CSIR, New Delhi, India, for doctoral fellowships. We thank Mr. L.M. Jha, IISERB, for crystal data, and Dr. Mithu Saha for DFT calculation.

Publisher Copyright:
© 2017 American Chemical Society.

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title = "Switchable Chemoselectivity for Organocatalytic, Asymmetric Malononitrile Addition to ortho-Formyl Chalcones",

abstract = "Chemoselective 1,2- and 1,4-addition of malononitriles to ortho-formyl chalcones using cinchona alkaloid based bifunctional chiral organocatalysts has been shown by tuning the electronic nature of the malononitriles. Alkyl (hard) malononitriles undergo an asymmetric 1,2-addition followed by oxa-Michael reaction cascade to afford 1,3-disubstituted isobenzofurans with high enantio- and diastereoselectivity. Aryl (soft) malononitriles proceed through 1,4-addition followed by an aldol reaction cascade to provide indanols, having three consecutive stereocenters, in good yields and with good to excellent enantio- and diastereoselectivites.",

author = "Sanjay Maity and Mithu Saha and Gurupada Hazra and Prasanta Ghorai",

note = "Funding Information: This work is funded by SERB (EMR/2016/005995), New Delhi, and IISER Bhopal. S.M. thanks UGC. M.S. thanks IISERB. G.H. thanks CSIR, New Delhi, India, for doctoral fellowships. We thank Mr. L.M. Jha, IISERB, for crystal data, and Dr. Mithu Saha for DFT calculation. Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

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AU - Hazra, Gurupada

AU - Ghorai, Prasanta

N1 - Funding Information: This work is funded by SERB (EMR/2016/005995), New Delhi, and IISER Bhopal. S.M. thanks UGC. M.S. thanks IISERB. G.H. thanks CSIR, New Delhi, India, for doctoral fellowships. We thank Mr. L.M. Jha, IISERB, for crystal data, and Dr. Mithu Saha for DFT calculation. Publisher Copyright: © 2017 American Chemical Society.

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N2 - Chemoselective 1,2- and 1,4-addition of malononitriles to ortho-formyl chalcones using cinchona alkaloid based bifunctional chiral organocatalysts has been shown by tuning the electronic nature of the malononitriles. Alkyl (hard) malononitriles undergo an asymmetric 1,2-addition followed by oxa-Michael reaction cascade to afford 1,3-disubstituted isobenzofurans with high enantio- and diastereoselectivity. Aryl (soft) malononitriles proceed through 1,4-addition followed by an aldol reaction cascade to provide indanols, having three consecutive stereocenters, in good yields and with good to excellent enantio- and diastereoselectivites.

AB - Chemoselective 1,2- and 1,4-addition of malononitriles to ortho-formyl chalcones using cinchona alkaloid based bifunctional chiral organocatalysts has been shown by tuning the electronic nature of the malononitriles. Alkyl (hard) malononitriles undergo an asymmetric 1,2-addition followed by oxa-Michael reaction cascade to afford 1,3-disubstituted isobenzofurans with high enantio- and diastereoselectivity. Aryl (soft) malononitriles proceed through 1,4-addition followed by an aldol reaction cascade to provide indanols, having three consecutive stereocenters, in good yields and with good to excellent enantio- and diastereoselectivites.

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Switchable Chemoselectivity for Organocatalytic, Asymmetric Malononitrile Addition to ortho-Formyl Chalcones

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