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

Sanjay Maity, Mithu Saha, Gurupada Hazra, Prasanta Ghorai

Research output: Contribution to journalArticlepeer-review

13 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 languageEnglish (US)
Pages (from-to)5872-5875
Number of pages4
JournalOrganic Letters
Volume19
Issue number21
DOIs
StatePublished - 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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